

<!--Generated by EDGARfilings PROfile 4.1.0.0 Copyright 1995 - 2015 Summit Financial Printing, LLC. All rights reserved.-->
<link:linkbase xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:t1="http://xbrl.org/2005/xbrldt">
  <link:roleRef roleURI="http://photronics.com/role/ScheduleIivaluationAndQualifyingAccountsDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#ScheduleIivaluationAndQualifyingAccountsDetails" />
  <link:roleRef roleURI="http://photronics.com/role/QuarterlyResultsOfOperationsUnauditedDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#QuarterlyResultsOfOperationsUnauditedDetails" />
  <link:roleRef roleURI="http://photronics.com/role/ExpansionIntoChinaDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#ExpansionIntoChinaDetails" />
  <link:roleRef roleURI="http://photronics.com/role/GainsOnSaleOfInvestmentsDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#GainsOnSaleOfInvestmentsDetails" />
  <link:roleRef roleURI="http://photronics.com/role/FairValueMeasurementsDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#FairValueMeasurementsDetails" />
  <link:roleRef roleURI="http://photronics.com/role/OtherRelatedPartyTransactionsDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#OtherRelatedPartyTransactionsDetails" />
  <link:roleRef roleURI="http://photronics.com/role/ChangesInAccumulatedOtherComprehensiveIncomeByComponentDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#ChangesInAccumulatedOtherComprehensiveIncomeByComponentDetails" />
  <link:roleRef roleURI="http://photronics.com/role/GeographicAndSignificantCustomerInformationDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#GeographicAndSignificantCustomerInformationDetails" />
  <link:roleRef roleURI="http://photronics.com/role/CommitmentsAndContingenciesDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#CommitmentsAndContingenciesDetails" />
  <link:roleRef roleURI="http://photronics.com/role/SubsidiaryShareRepurchaseDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#SubsidiaryShareRepurchaseDetails" />
  <link:roleRef roleURI="http://photronics.com/role/EarningsPerShareDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#EarningsPerShareDetails" />
  <link:roleRef roleURI="http://photronics.com/role/IncomeTaxesDetailsCalc01" xlink:type="simple" xlink:href="plab-20161030.xsd#IncomeTaxesDetailsCalc01" />
  <link:roleRef roleURI="http://photronics.com/role/IncomeTaxesUnrecognizedTaxBenefitsAndCarryforwardsDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#IncomeTaxesUnrecognizedTaxBenefitsAndCarryforwardsDetails" />
  <link:roleRef roleURI="http://photronics.com/role/IncomeTaxesDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#IncomeTaxesDetails" />
  <link:roleRef roleURI="http://photronics.com/role/EmployeeRetirementPlansDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#EmployeeRetirementPlansDetails" />
  <link:roleRef roleURI="http://photronics.com/role/SharebasedCompensationDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#SharebasedCompensationDetails" />
  <link:roleRef roleURI="http://photronics.com/role/OperatingLeasesDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#OperatingLeasesDetails" />
  <link:roleRef roleURI="http://photronics.com/role/LongtermBorrowingsDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#LongtermBorrowingsDetails" />
  <link:roleRef roleURI="http://photronics.com/role/AccruedLiabilitiesDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#AccruedLiabilitiesDetails" />
  <link:roleRef roleURI="http://photronics.com/role/JointVentureTechnologyLicenseAndOtherAgreementsWithMicronTechnologyIncDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#JointVentureTechnologyLicenseAndOtherAgreementsWithMicronTechnologyIncDetails" />
  <link:roleRef roleURI="http://photronics.com/role/IntangibleAssetsDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#IntangibleAssetsDetails" />
  <link:roleRef roleURI="http://photronics.com/role/PropertyPlantAndEquipmentDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#PropertyPlantAndEquipmentDetails" />
  <link:roleRef roleURI="http://photronics.com/role/AcquisitionOfDnpPhotomaskTechnologyTaiwanCoLtdProFormaInformationDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#AcquisitionOfDnpPhotomaskTechnologyTaiwanCoLtdProFormaInformationDetails" />
  <link:roleRef roleURI="http://photronics.com/role/AcquisitionOfDnpPhotomaskTechnologyTaiwanCoLtdFairValuesOfAssetsAcquiredAndLiabilitiesAssumedDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#AcquisitionOfDnpPhotomaskTechnologyTaiwanCoLtdFairValuesOfAssetsAcquiredAndLiabilitiesAssumedDetails" />
  <link:roleRef roleURI="http://photronics.com/role/AcquisitionOfDnpPhotomaskTechnologyTaiwanCoLtdDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#AcquisitionOfDnpPhotomaskTechnologyTaiwanCoLtdDetails" />
  <link:roleRef roleURI="http://photronics.com/role/SummaryOfSignificantAccountingPoliciesDetails" xlink:type="simple" xlink:href="plab-20161030.xsd#SummaryOfSignificantAccountingPoliciesDetails" />
  <link:roleRef roleURI="http://photronics.com/role/QuarterlyResultsOfOperationsUnauditedTables" xlink:type="simple" xlink:href="plab-20161030.xsd#QuarterlyResultsOfOperationsUnauditedTables" />
  <link:roleRef roleURI="http://photronics.com/role/FairValueMeasurementsTables" xlink:type="simple" xlink:href="plab-20161030.xsd#FairValueMeasurementsTables" />
  <link:roleRef roleURI="http://photronics.com/role/ChangesInAccumulatedOtherComprehensiveIncomeByComponentTables" xlink:type="simple" xlink:href="plab-20161030.xsd#ChangesInAccumulatedOtherComprehensiveIncomeByComponentTables" />
  <link:roleRef roleURI="http://photronics.com/role/GeographicAndSignificantCustomerInformationTables" xlink:type="simple" xlink:href="plab-20161030.xsd#GeographicAndSignificantCustomerInformationTables" />
  <link:roleRef roleURI="http://photronics.com/role/SubsidiaryShareRepurchaseTables" xlink:type="simple" xlink:href="plab-20161030.xsd#SubsidiaryShareRepurchaseTables" />
  <link:roleRef roleURI="http://photronics.com/role/EarningsPerShareTables" xlink:type="simple" xlink:href="plab-20161030.xsd#EarningsPerShareTables" />
  <link:roleRef roleURI="http://photronics.com/role/IncomeTaxesTables" xlink:type="simple" xlink:href="plab-20161030.xsd#IncomeTaxesTables" />
  <link:roleRef roleURI="http://photronics.com/role/SharebasedCompensationTables" xlink:type="simple" xlink:href="plab-20161030.xsd#SharebasedCompensationTables" />
  <link:roleRef roleURI="http://photronics.com/role/OperatingLeasesTables" xlink:type="simple" xlink:href="plab-20161030.xsd#OperatingLeasesTables" />
  <link:roleRef roleURI="http://photronics.com/role/LongtermBorrowingsTables" xlink:type="simple" xlink:href="plab-20161030.xsd#LongtermBorrowingsTables" />
  <link:roleRef roleURI="http://photronics.com/role/JointVentureTechnologyLicenseAndOtherAgreementsWithMicronTechnologyIncTables" xlink:type="simple" xlink:href="plab-20161030.xsd#JointVentureTechnologyLicenseAndOtherAgreementsWithMicronTechnologyIncTables" />
  <link:roleRef roleURI="http://photronics.com/role/IntangibleAssetsTables" xlink:type="simple" xlink:href="plab-20161030.xsd#IntangibleAssetsTables" />
  <link:roleRef roleURI="http://photronics.com/role/PropertyPlantAndEquipmentTables" xlink:type="simple" xlink:href="plab-20161030.xsd#PropertyPlantAndEquipmentTables" />
  <link:roleRef roleURI="http://photronics.com/role/AcquisitionOfDnpPhotomaskTechnologyTaiwanCoLtdTables" xlink:type="simple" xlink:href="plab-20161030.xsd#AcquisitionOfDnpPhotomaskTechnologyTaiwanCoLtdTables" />
  <link:roleRef roleURI="http://photronics.com/role/SummaryOfSignificantAccountingPoliciesTables" xlink:type="simple" xlink:href="plab-20161030.xsd#SummaryOfSignificantAccountingPoliciesTables" />
  <link:roleRef roleURI="http://photronics.com/role/RecentAccountingPronouncementsPolicies" xlink:type="simple" xlink:href="plab-20161030.xsd#RecentAccountingPronouncementsPolicies" />
  <link:roleRef roleURI="http://photronics.com/role/FairValueMeasurementsPolicies" xlink:type="simple" xlink:href="plab-20161030.xsd#FairValueMeasurementsPolicies" />
  <link:roleRef roleURI="http://photronics.com/role/IncomeTaxesPolicies" xlink:type="simple" xlink:href="plab-20161030.xsd#IncomeTaxesPolicies" />
  <link:roleRef roleURI="http://photronics.com/role/SharebasedCompensationPolicies" xlink:type="simple" xlink:href="plab-20161030.xsd#SharebasedCompensationPolicies" />
  <link:roleRef roleURI="http://photronics.com/role/AcquisitionOfDnpPhotomaskTechnologyTaiwanCoLtdPolicies" xlink:type="simple" xlink:href="plab-20161030.xsd#AcquisitionOfDnpPhotomaskTechnologyTaiwanCoLtdPolicies" />
  <link:roleRef roleURI="http://photronics.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:type="simple" xlink:href="plab-20161030.xsd#SummaryOfSignificantAccountingPoliciesPolicies" />
  <link:roleRef roleURI="http://photronics.com/role/ScheduleIivaluationAndQualifyingAccounts" xlink:type="simple" xlink:href="plab-20161030.xsd#ScheduleIivaluationAndQualifyingAccounts" />
  <link:roleRef roleURI="http://photronics.com/role/RecentAccountingPronouncements" xlink:type="simple" xlink:href="plab-20161030.xsd#RecentAccountingPronouncements" />
  <link:roleRef roleURI="http://photronics.com/role/QuarterlyResultsOfOperationsUnaudited" xlink:type="simple" xlink:href="plab-20161030.xsd#QuarterlyResultsOfOperationsUnaudited" />
  <link:roleRef roleURI="http://photronics.com/role/ExpansionIntoChina" xlink:type="simple" xlink:href="plab-20161030.xsd#ExpansionIntoChina" />
  <link:roleRef roleURI="http://photronics.com/role/GainsOnSaleOfInvestments" xlink:type="simple" xlink:href="plab-20161030.xsd#GainsOnSaleOfInvestments" />
  <link:roleRef roleURI="http://photronics.com/role/FairValueMeasurements" xlink:type="simple" xlink:href="plab-20161030.xsd#FairValueMeasurements" />
  <link:roleRef roleURI="http://photronics.com/role/OtherRelatedPartyTransactions" xlink:type="simple" xlink:href="plab-20161030.xsd#OtherRelatedPartyTransactions" />
  <link:roleRef roleURI="http://photronics.com/role/ConcentrationsOfCreditRisk" xlink:type="simple" xlink:href="plab-20161030.xsd#ConcentrationsOfCreditRisk" />
  <link:roleRef roleURI="http://photronics.com/role/ChangesInAccumulatedOtherComprehensiveIncomeByComponent" xlink:type="simple" xlink:href="plab-20161030.xsd#ChangesInAccumulatedOtherComprehensiveIncomeByComponent" />
  <link:roleRef roleURI="http://photronics.com/role/GeographicAndSignificantCustomerInformation" xlink:type="simple" xlink:href="plab-20161030.xsd#GeographicAndSignificantCustomerInformation" />
  <link:roleRef roleURI="http://photronics.com/role/CommitmentsAndContingencies" xlink:type="simple" xlink:href="plab-20161030.xsd#CommitmentsAndContingencies" />
  <link:roleRef roleURI="http://photronics.com/role/SubsidiaryShareRepurchase" xlink:type="simple" xlink:href="plab-20161030.xsd#SubsidiaryShareRepurchase" />
  <link:roleRef roleURI="http://photronics.com/role/EarningsPerShare" xlink:type="simple" xlink:href="plab-20161030.xsd#EarningsPerShare" />
  <link:roleRef roleURI="http://photronics.com/role/IncomeTaxes" xlink:type="simple" xlink:href="plab-20161030.xsd#IncomeTaxes" />
  <link:roleRef roleURI="http://photronics.com/role/EmployeeRetirementPlans" xlink:type="simple" xlink:href="plab-20161030.xsd#EmployeeRetirementPlans" />
  <link:roleRef roleURI="http://photronics.com/role/SharebasedCompensation" xlink:type="simple" xlink:href="plab-20161030.xsd#SharebasedCompensation" />
  <link:roleRef roleURI="http://photronics.com/role/OperatingLeases" xlink:type="simple" xlink:href="plab-20161030.xsd#OperatingLeases" />
  <link:roleRef roleURI="http://photronics.com/role/LongtermBorrowings" xlink:type="simple" xlink:href="plab-20161030.xsd#LongtermBorrowings" />
  <link:roleRef roleURI="http://photronics.com/role/AccruedLiabilities" xlink:type="simple" xlink:href="plab-20161030.xsd#AccruedLiabilities" />
  <link:roleRef roleURI="http://photronics.com/role/JointVentureTechnologyLicenseAndOtherAgreementsWithMicronTechnologyInc" xlink:type="simple" xlink:href="plab-20161030.xsd#JointVentureTechnologyLicenseAndOtherAgreementsWithMicronTechnologyInc" />
  <link:roleRef roleURI="http://photronics.com/role/IntangibleAssets" xlink:type="simple" xlink:href="plab-20161030.xsd#IntangibleAssets" />
  <link:roleRef roleURI="http://photronics.com/role/PropertyPlantAndEquipment" xlink:type="simple" xlink:href="plab-20161030.xsd#PropertyPlantAndEquipment" />
  <link:roleRef roleURI="http://photronics.com/role/AcquisitionOfDnpPhotomaskTechnologyTaiwanCoLtd" xlink:type="simple" xlink:href="plab-20161030.xsd#AcquisitionOfDnpPhotomaskTechnologyTaiwanCoLtd" />
  <link:roleRef roleURI="http://photronics.com/role/SummaryOfSignificantAccountingPolicies" xlink:type="simple" xlink:href="plab-20161030.xsd#SummaryOfSignificantAccountingPolicies" />
  <link:roleRef roleURI="http://photronics.com/role/ConsolidatedStatementsOfCashFlows" xlink:type="simple" xlink:href="plab-20161030.xsd#ConsolidatedStatementsOfCashFlows" />
  <link:roleRef roleURI="http://photronics.com/role/ConsolidatedStatementsOfEquity" xlink:type="simple" xlink:href="plab-20161030.xsd#ConsolidatedStatementsOfEquity" />
  <link:roleRef roleURI="http://photronics.com/role/ConsolidatedStatementsOfComprehensiveIncomeParenthetical" xlink:type="simple" xlink:href="plab-20161030.xsd#ConsolidatedStatementsOfComprehensiveIncomeParenthetical" />
  <link:roleRef roleURI="http://photronics.com/role/ConsolidatedStatementsOfComprehensiveIncome" xlink:type="simple" xlink:href="plab-20161030.xsd#ConsolidatedStatementsOfComprehensiveIncome" />
  <link:roleRef roleURI="http://photronics.com/role/ConsolidatedStatementsOfIncome" xlink:type="simple" xlink:href="plab-20161030.xsd#ConsolidatedStatementsOfIncome" />
  <link:roleRef roleURI="http://photronics.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="simple" xlink:href="plab-20161030.xsd#ConsolidatedBalanceSheetsParenthetical" />
  <link:roleRef roleURI="http://photronics.com/role/ConsolidatedBalanceSheets" xlink:type="simple" xlink:href="plab-20161030.xsd#ConsolidatedBalanceSheets" />
  <link:roleRef roleURI="http://photronics.com/role/DocumentAndEntityInformation" xlink:type="simple" xlink:href="plab-20161030.xsd#DocumentAndEntityInformation" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/DocumentAndEntityInformation" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/ConsolidatedBalanceSheets" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/ConsolidatedBalanceSheetsParenthetical" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/ConsolidatedStatementsOfIncome" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/ConsolidatedStatementsOfComprehensiveIncome" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/ConsolidatedStatementsOfComprehensiveIncomeParenthetical" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/ConsolidatedStatementsOfEquity">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementLineItems" xlink:label="StatementLineItems" xlink:title="StatementLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:title="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:title="definition: StatementLineItems to StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SharesOutstanding" xlink:label="SharesOutstanding" xlink:title="SharesOutstanding" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="SharesOutstanding" xlink:title="definition: StatementLineItems to SharesOutstanding" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProfitLoss" xlink:label="ProfitLoss" xlink:title="ProfitLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="ProfitLoss" xlink:title="definition: StatementLineItems to ProfitLoss" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:label="OtherComprehensiveIncomeLossNetOfTax" xlink:title="OtherComprehensiveIncomeLossNetOfTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="OtherComprehensiveIncomeLossNetOfTax" xlink:title="definition: StatementLineItems to OtherComprehensiveIncomeLossNetOfTax" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation" xlink:label="StockIssuedDuringPeriodValueShareBasedCompensation" xlink:title="StockIssuedDuringPeriodValueShareBasedCompensation" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodValueShareBasedCompensation" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodValueShareBasedCompensation" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:label="StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:title="StockIssuedDuringPeriodSharesShareBasedCompensation" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodSharesShareBasedCompensation" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures" xlink:label="StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures" xlink:title="StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures" xlink:label="StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures" xlink:title="StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures" xlink:title="definition: StatementLineItems to StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:label="AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:title="AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:title="definition: StatementLineItems to AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance" xlink:label="NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance" xlink:title="NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance" xlink:title="definition: StatementLineItems to NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtConversionConvertedInstrumentAmount1" xlink:label="DebtConversionConvertedInstrumentAmount1" xlink:title="DebtConversionConvertedInstrumentAmount1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="DebtConversionConvertedInstrumentAmount1" xlink:title="definition: StatementLineItems to DebtConversionConvertedInstrumentAmount1" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtConversionConvertedInstrumentSharesIssued1" xlink:label="DebtConversionConvertedInstrumentSharesIssued1" xlink:title="DebtConversionConvertedInstrumentSharesIssued1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="DebtConversionConvertedInstrumentSharesIssued1" xlink:title="definition: StatementLineItems to DebtConversionConvertedInstrumentSharesIssued1" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_Dividends" xlink:label="Dividends" xlink:title="Dividends" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="Dividends" xlink:title="definition: StatementLineItems to Dividends" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_ReturnOfCapitalToNoncontrollingInterests" xlink:label="ReturnOfCapitalToNoncontrollingInterests" xlink:title="ReturnOfCapitalToNoncontrollingInterests" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="ReturnOfCapitalToNoncontrollingInterests" xlink:title="definition: StatementLineItems to ReturnOfCapitalToNoncontrollingInterests" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MinorityInterestDecreaseFromRedemptions" xlink:label="MinorityInterestDecreaseFromRedemptions" xlink:title="MinorityInterestDecreaseFromRedemptions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="MinorityInterestDecreaseFromRedemptions" xlink:title="definition: StatementLineItems to MinorityInterestDecreaseFromRedemptions" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementTable" xlink:label="StatementTable" xlink:title="StatementTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="StatementLineItems" xlink:to="StatementTable" xlink:title="definition: StatementLineItems to StatementTable" order="16.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="StatementEquityComponentsAxis" xlink:title="StatementEquityComponentsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="StatementTable" xlink:to="StatementEquityComponentsAxis" xlink:title="definition: StatementTable to StatementEquityComponentsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain_2" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain_2" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CommonStockMember" xlink:label="CommonStockMember" xlink:title="CommonStockMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="CommonStockMember" xlink:title="definition: EquityComponentDomain to CommonStockMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="AdditionalPaidInCapitalMember" xlink:title="AdditionalPaidInCapitalMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="AdditionalPaidInCapitalMember" xlink:title="definition: EquityComponentDomain to AdditionalPaidInCapitalMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="RetainedEarningsMember" xlink:title="RetainedEarningsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="RetainedEarningsMember" xlink:title="definition: EquityComponentDomain to RetainedEarningsMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="AccumulatedOtherComprehensiveIncomeMember" xlink:title="AccumulatedOtherComprehensiveIncomeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="AccumulatedOtherComprehensiveIncomeMember" xlink:title="definition: EquityComponentDomain to AccumulatedOtherComprehensiveIncomeMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NoncontrollingInterestMember" xlink:label="NoncontrollingInterestMember" xlink:title="NoncontrollingInterestMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="NoncontrollingInterestMember" xlink:title="definition: EquityComponentDomain to NoncontrollingInterestMember" order="5.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/ConsolidatedStatementsOfCashFlows" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/SummaryOfSignificantAccountingPolicies" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/AcquisitionOfDnpPhotomaskTechnologyTaiwanCoLtd" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/PropertyPlantAndEquipment" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/IntangibleAssets" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/JointVentureTechnologyLicenseAndOtherAgreementsWithMicronTechnologyInc" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/AccruedLiabilities" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/LongtermBorrowings" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/OperatingLeases" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/SharebasedCompensation" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/EmployeeRetirementPlans" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/IncomeTaxes" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/EarningsPerShare" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/SubsidiaryShareRepurchase" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/CommitmentsAndContingencies" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/GeographicAndSignificantCustomerInformation" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/ChangesInAccumulatedOtherComprehensiveIncomeByComponent" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/ConcentrationsOfCreditRisk" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/OtherRelatedPartyTransactions" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/FairValueMeasurements" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/GainsOnSaleOfInvestments" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/ExpansionIntoChina" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/QuarterlyResultsOfOperationsUnaudited" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/RecentAccountingPronouncements" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/ScheduleIivaluationAndQualifyingAccounts" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/SummaryOfSignificantAccountingPoliciesPolicies" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/AcquisitionOfDnpPhotomaskTechnologyTaiwanCoLtdPolicies">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="BusinessAcquisitionLineItems" xlink:title="BusinessAcquisitionLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationsPolicy" xlink:label="BusinessCombinationsPolicy" xlink:title="BusinessCombinationsPolicy" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationsPolicy" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationsPolicy" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:title="ScheduleOfBusinessAcquisitionsByAcquisitionTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="BusinessAcquisitionLineItems" xlink:to="ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:title="definition: BusinessAcquisitionLineItems to ScheduleOfBusinessAcquisitionsByAcquisitionTable" order="2.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="BusinessAcquisitionAxis" xlink:title="BusinessAcquisitionAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="BusinessAcquisitionAxis" xlink:title="definition: ScheduleOfBusinessAcquisitionsByAcquisitionTable to BusinessAcquisitionAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain_2" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain_2" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_DnpPhotomaskTechnologyTaiwanCoLtdDpttMember" xlink:label="DnpPhotomaskTechnologyTaiwanCoLtdDpttMember" xlink:title="DnpPhotomaskTechnologyTaiwanCoLtdDpttMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="DnpPhotomaskTechnologyTaiwanCoLtdDpttMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to DnpPhotomaskTechnologyTaiwanCoLtdDpttMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/SharebasedCompensationPolicies">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy" xlink:label="ShareBasedCompensationOptionAndIncentivePlansPolicy" xlink:title="ShareBasedCompensationOptionAndIncentivePlansPolicy" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationOptionAndIncentivePlansPolicy" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationOptionAndIncentivePlansPolicy" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="2.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="AwardTypeAxis" xlink:title="AwardTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="AwardTypeAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to AwardTypeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="EmployeeStockOptionMember" xlink:title="EmployeeStockOptionMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="EmployeeStockOptionMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to EmployeeStockOptionMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RestrictedStockMember" xlink:label="RestrictedStockMember" xlink:title="RestrictedStockMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="RestrictedStockMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to RestrictedStockMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EmployeeStockMember" xlink:label="EmployeeStockMember" xlink:title="EmployeeStockMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="EmployeeStockMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to EmployeeStockMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_UnvestedOptionsMember" xlink:label="UnvestedOptionsMember" xlink:title="UnvestedOptionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="UnvestedOptionsMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to UnvestedOptionsMember" order="4.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/IncomeTaxesPolicies" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/FairValueMeasurementsPolicies" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/RecentAccountingPronouncementsPolicies" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/SummaryOfSignificantAccountingPoliciesTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/AcquisitionOfDnpPhotomaskTechnologyTaiwanCoLtdTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/PropertyPlantAndEquipmentTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/IntangibleAssetsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/JointVentureTechnologyLicenseAndOtherAgreementsWithMicronTechnologyIncTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/LongtermBorrowingsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/OperatingLeasesTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/SharebasedCompensationTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/IncomeTaxesTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/EarningsPerShareTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/SubsidiaryShareRepurchaseTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/GeographicAndSignificantCustomerInformationTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/ChangesInAccumulatedOtherComprehensiveIncomeByComponentTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/FairValueMeasurementsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/QuarterlyResultsOfOperationsUnauditedTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/SummaryOfSignificantAccountingPoliciesDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MinorityInterestLineItems" xlink:label="MinorityInterestLineItems" xlink:title="MinorityInterestLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NoncontrollingInterestAbstract" xlink:label="NoncontrollingInterestAbstract" xlink:title="NoncontrollingInterestAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="MinorityInterestLineItems" xlink:to="NoncontrollingInterestAbstract" xlink:title="definition: MinorityInterestLineItems to NoncontrollingInterestAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_NumberOfMajorityOwnedSubsidiaries" xlink:label="NumberOfMajorityOwnedSubsidiaries" xlink:title="NumberOfMajorityOwnedSubsidiaries" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="MinorityInterestLineItems" xlink:to="NumberOfMajorityOwnedSubsidiaries" xlink:title="definition: MinorityInterestLineItems to NumberOfMajorityOwnedSubsidiaries" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners" xlink:label="MinorityInterestOwnershipPercentageByNoncontrollingOwners" xlink:title="MinorityInterestOwnershipPercentageByNoncontrollingOwners" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="MinorityInterestLineItems" xlink:to="MinorityInterestOwnershipPercentageByNoncontrollingOwners" xlink:title="definition: MinorityInterestLineItems to MinorityInterestOwnershipPercentageByNoncontrollingOwners" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MinorityInterestTable" xlink:label="MinorityInterestTable" xlink:title="MinorityInterestTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="MinorityInterestLineItems" xlink:to="MinorityInterestTable" xlink:title="definition: MinorityInterestLineItems to MinorityInterestTable" order="4.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="LegalEntityAxis" xlink:title="LegalEntityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="MinorityInterestTable" xlink:to="LegalEntityAxis" xlink:title="definition: MinorityInterestTable to LegalEntityAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain" xlink:title="EntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LegalEntityAxis" xlink:to="EntityDomain" xlink:title="definition: LegalEntityAxis to EntityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain_2" xlink:title="EntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LegalEntityAxis" xlink:to="EntityDomain_2" xlink:title="definition: LegalEntityAxis to EntityDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_PkLtdMember" xlink:label="PkLtdMember" xlink:title="PkLtdMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="PkLtdMember" xlink:title="definition: EntityDomain to PkLtdMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_PhotronicsDnpMaskCorporationPdmcMember" xlink:label="PhotronicsDnpMaskCorporationPdmcMember" xlink:title="PhotronicsDnpMaskCorporationPdmcMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="PhotronicsDnpMaskCorporationPdmcMember" xlink:title="definition: EntityDomain to PhotronicsDnpMaskCorporationPdmcMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:label="FiniteLivedIntangibleAssetsLineItems" xlink:title="FiniteLivedIntangibleAssetsLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:label="FiniteLivedIntangibleAssetUsefulLife" xlink:title="FiniteLivedIntangibleAssetUsefulLife" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetUsefulLife" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetUsefulLife" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:label="ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:title="ScheduleOfFiniteLivedIntangibleAssetsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to ScheduleOfFiniteLivedIntangibleAssetsTable" order="2.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:to="RangeAxis" xlink:title="definition: ScheduleOfFiniteLivedIntangibleAssetsTable to RangeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeMember" xlink:label="RangeMember" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeMember" xlink:title="definition: RangeAxis to RangeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeMember" xlink:label="RangeMember_2" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeMember_2" xlink:title="definition: RangeAxis to RangeMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MinimumMember" xlink:label="MinimumMember" xlink:title="MinimumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MinimumMember" xlink:title="definition: RangeMember to MinimumMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MaximumMember" xlink:label="MaximumMember" xlink:title="MaximumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MaximumMember" xlink:title="definition: RangeMember to MaximumMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="PropertyPlantAndEquipmentLineItems" xlink:title="PropertyPlantAndEquipmentLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentAbstract" xlink:label="PropertyPlantAndEquipmentAbstract" xlink:title="PropertyPlantAndEquipmentAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="PropertyPlantAndEquipmentAbstract" xlink:title="definition: PropertyPlantAndEquipmentLineItems to PropertyPlantAndEquipmentAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:label="PropertyPlantAndEquipmentUsefulLife" xlink:title="PropertyPlantAndEquipmentUsefulLife" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="PropertyPlantAndEquipmentUsefulLife" xlink:title="definition: PropertyPlantAndEquipmentLineItems to PropertyPlantAndEquipmentUsefulLife" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="ScheduleOfPropertyPlantAndEquipmentTable" xlink:title="ScheduleOfPropertyPlantAndEquipmentTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="ScheduleOfPropertyPlantAndEquipmentTable" xlink:title="definition: PropertyPlantAndEquipmentLineItems to ScheduleOfPropertyPlantAndEquipmentTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="PropertyPlantAndEquipmentByTypeAxis" xlink:title="PropertyPlantAndEquipmentByTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfPropertyPlantAndEquipmentTable" xlink:to="PropertyPlantAndEquipmentByTypeAxis" xlink:title="definition: ScheduleOfPropertyPlantAndEquipmentTable to PropertyPlantAndEquipmentByTypeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="PropertyPlantAndEquipmentTypeDomain" xlink:title="PropertyPlantAndEquipmentTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="PropertyPlantAndEquipmentByTypeAxis" xlink:to="PropertyPlantAndEquipmentTypeDomain" xlink:title="definition: PropertyPlantAndEquipmentByTypeAxis to PropertyPlantAndEquipmentTypeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="PropertyPlantAndEquipmentTypeDomain_2" xlink:title="PropertyPlantAndEquipmentTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="PropertyPlantAndEquipmentByTypeAxis" xlink:to="PropertyPlantAndEquipmentTypeDomain_2" xlink:title="definition: PropertyPlantAndEquipmentByTypeAxis to PropertyPlantAndEquipmentTypeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BuildingImprovementsMember" xlink:label="BuildingImprovementsMember" xlink:title="BuildingImprovementsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="BuildingImprovementsMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to BuildingImprovementsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MachineryAndEquipmentMember" xlink:label="MachineryAndEquipmentMember" xlink:title="MachineryAndEquipmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="MachineryAndEquipmentMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to MachineryAndEquipmentMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FurnitureAndFixturesMember" xlink:label="FurnitureAndFixturesMember" xlink:title="FurnitureAndFixturesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="FurnitureAndFixturesMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to FurnitureAndFixturesMember" order="3.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfPropertyPlantAndEquipmentTable" xlink:to="RangeAxis" xlink:title="definition: ScheduleOfPropertyPlantAndEquipmentTable to RangeAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_ManufacturingFacilitiesByGeographicalRegionLineItems" xlink:label="ManufacturingFacilitiesByGeographicalRegionLineItems" xlink:title="ManufacturingFacilitiesByGeographicalRegionLineItems" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_NumberOfManufacturingFacilities" xlink:label="NumberOfManufacturingFacilities" xlink:title="NumberOfManufacturingFacilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ManufacturingFacilitiesByGeographicalRegionLineItems" xlink:to="NumberOfManufacturingFacilities" xlink:title="definition: ManufacturingFacilitiesByGeographicalRegionLineItems to NumberOfManufacturingFacilities" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_FacilityConstructionStartDate" xlink:label="FacilityConstructionStartDate" xlink:title="FacilityConstructionStartDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ManufacturingFacilitiesByGeographicalRegionLineItems" xlink:to="FacilityConstructionStartDate" xlink:title="definition: ManufacturingFacilitiesByGeographicalRegionLineItems to FacilityConstructionStartDate" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_FacilityProductionStartDate" xlink:label="FacilityProductionStartDate" xlink:title="FacilityProductionStartDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ManufacturingFacilitiesByGeographicalRegionLineItems" xlink:to="FacilityProductionStartDate" xlink:title="definition: ManufacturingFacilitiesByGeographicalRegionLineItems to FacilityProductionStartDate" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_ManufacturingFacilitiesByGeographicalRegionTable" xlink:label="ManufacturingFacilitiesByGeographicalRegionTable" xlink:title="ManufacturingFacilitiesByGeographicalRegionTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ManufacturingFacilitiesByGeographicalRegionLineItems" xlink:to="ManufacturingFacilitiesByGeographicalRegionTable" xlink:title="definition: ManufacturingFacilitiesByGeographicalRegionLineItems to ManufacturingFacilitiesByGeographicalRegionTable" order="4.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementGeographicalAxis" xlink:label="StatementGeographicalAxis" xlink:title="StatementGeographicalAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ManufacturingFacilitiesByGeographicalRegionTable" xlink:to="StatementGeographicalAxis" xlink:title="definition: ManufacturingFacilitiesByGeographicalRegionTable to StatementGeographicalAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="SegmentGeographicalDomain" xlink:title="SegmentGeographicalDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementGeographicalAxis" xlink:to="SegmentGeographicalDomain" xlink:title="definition: StatementGeographicalAxis to SegmentGeographicalDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="SegmentGeographicalDomain_2" xlink:title="SegmentGeographicalDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementGeographicalAxis" xlink:to="SegmentGeographicalDomain_2" xlink:title="definition: StatementGeographicalAxis to SegmentGeographicalDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EuropeMember" xlink:label="EuropeMember" xlink:title="EuropeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="EuropeMember" xlink:title="definition: SegmentGeographicalDomain to EuropeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/country/2016/country-2016-01-31.xsd#country_TW" xlink:label="TW" xlink:title="TW" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="TW" xlink:title="definition: SegmentGeographicalDomain to TW" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/country/2016/country-2016-01-31.xsd#country_KR" xlink:label="KR" xlink:title="KR" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="KR" xlink:title="definition: SegmentGeographicalDomain to KR" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/country/2016/country-2016-01-31.xsd#country_US" xlink:label="US" xlink:title="US" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="US" xlink:title="definition: SegmentGeographicalDomain to US" order="4.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/AcquisitionOfDnpPhotomaskTechnologyTaiwanCoLtdDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="BusinessAcquisitionLineItems" xlink:title="BusinessAcquisitionLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionEffectiveDateOfAcquisition1" xlink:label="BusinessAcquisitionEffectiveDateOfAcquisition1" xlink:title="BusinessAcquisitionEffectiveDateOfAcquisition1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessAcquisitionEffectiveDateOfAcquisition1" xlink:title="definition: BusinessAcquisitionLineItems to BusinessAcquisitionEffectiveDateOfAcquisition1" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="BusinessCombinationConsiderationTransferred1" xlink:title="BusinessCombinationConsiderationTransferred1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationConsiderationTransferred1" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationConsiderationTransferred1" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired" xlink:label="BusinessAcquisitionPercentageOfVotingInterestsAcquired" xlink:title="BusinessAcquisitionPercentageOfVotingInterestsAcquired" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessAcquisitionPercentageOfVotingInterestsAcquired" xlink:title="definition: BusinessAcquisitionLineItems to BusinessAcquisitionPercentageOfVotingInterestsAcquired" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners" xlink:label="MinorityInterestOwnershipPercentageByNoncontrollingOwners" xlink:title="MinorityInterestOwnershipPercentageByNoncontrollingOwners" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="MinorityInterestOwnershipPercentageByNoncontrollingOwners" xlink:title="definition: BusinessAcquisitionLineItems to MinorityInterestOwnershipPercentageByNoncontrollingOwners" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationAcquisitionRelatedCosts" xlink:label="BusinessCombinationAcquisitionRelatedCosts" xlink:title="BusinessCombinationAcquisitionRelatedCosts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationAcquisitionRelatedCosts" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationAcquisitionRelatedCosts" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_Depreciation" xlink:label="Depreciation" xlink:title="Depreciation" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="Depreciation" xlink:title="definition: BusinessAcquisitionLineItems to Depreciation" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual" xlink:label="BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual" xlink:title="BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual" xlink:label="BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual" xlink:title="BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:label="FiniteLivedIntangibleAssetUsefulLife" xlink:title="FiniteLivedIntangibleAssetUsefulLife" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="FiniteLivedIntangibleAssetUsefulLife" xlink:title="definition: BusinessAcquisitionLineItems to FiniteLivedIntangibleAssetUsefulLife" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued" xlink:label="BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued" xlink:title="BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued" xlink:title="definition: BusinessAcquisitionLineItems to BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:title="ScheduleOfBusinessAcquisitionsByAcquisitionTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="BusinessAcquisitionLineItems" xlink:to="ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:title="definition: BusinessAcquisitionLineItems to ScheduleOfBusinessAcquisitionsByAcquisitionTable" order="11.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="BusinessAcquisitionAxis" xlink:title="BusinessAcquisitionAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="BusinessAcquisitionAxis" xlink:title="definition: ScheduleOfBusinessAcquisitionsByAcquisitionTable to BusinessAcquisitionAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain_2" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain_2" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_DnpPhotomaskTechnologyTaiwanCoLtdDpttMember" xlink:label="DnpPhotomaskTechnologyTaiwanCoLtdDpttMember" xlink:title="DnpPhotomaskTechnologyTaiwanCoLtdDpttMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="DnpPhotomaskTechnologyTaiwanCoLtdDpttMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to DnpPhotomaskTechnologyTaiwanCoLtdDpttMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_PhotronicsDnpMaskCorporationPdmcMember" xlink:label="PhotronicsDnpMaskCorporationPdmcMember" xlink:title="PhotronicsDnpMaskCorporationPdmcMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="PhotronicsDnpMaskCorporationPdmcMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to PhotronicsDnpMaskCorporationPdmcMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="LegalEntityAxis" xlink:title="LegalEntityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="LegalEntityAxis" xlink:title="definition: ScheduleOfBusinessAcquisitionsByAcquisitionTable to LegalEntityAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain" xlink:title="EntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LegalEntityAxis" xlink:to="EntityDomain" xlink:title="definition: LegalEntityAxis to EntityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain_2" xlink:title="EntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LegalEntityAxis" xlink:to="EntityDomain_2" xlink:title="definition: LegalEntityAxis to EntityDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CoVenturerMember" xlink:label="CoVenturerMember" xlink:title="CoVenturerMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="CoVenturerMember" xlink:title="definition: EntityDomain to CoVenturerMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_PhotronicsSemiconductorMaskCorporationMember" xlink:label="PhotronicsSemiconductorMaskCorporationMember" xlink:title="PhotronicsSemiconductorMaskCorporationMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="PhotronicsSemiconductorMaskCorporationMember" xlink:title="definition: EntityDomain to PhotronicsSemiconductorMaskCorporationMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:title="FiniteLivedIntangibleAssetsByMajorClassAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:title="definition: ScheduleOfBusinessAcquisitionsByAcquisitionTable to FiniteLivedIntangibleAssetsByMajorClassAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:title="FiniteLivedIntangibleAssetsMajorClassNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:title="definition: FiniteLivedIntangibleAssetsByMajorClassAxis to FiniteLivedIntangibleAssetsMajorClassNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="FiniteLivedIntangibleAssetsMajorClassNameDomain_2" xlink:title="FiniteLivedIntangibleAssetsMajorClassNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="FiniteLivedIntangibleAssetsMajorClassNameDomain_2" xlink:title="definition: FiniteLivedIntangibleAssetsByMajorClassAxis to FiniteLivedIntangibleAssetsMajorClassNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CustomerRelationshipsMember" xlink:label="CustomerRelationshipsMember" xlink:title="CustomerRelationshipsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="CustomerRelationshipsMember" xlink:title="definition: FiniteLivedIntangibleAssetsMajorClassNameDomain to CustomerRelationshipsMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/AcquisitionOfDnpPhotomaskTechnologyTaiwanCoLtdFairValuesOfAssetsAcquiredAndLiabilitiesAssumedDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="BusinessAcquisitionLineItems" xlink:title="BusinessAcquisitionLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetAbstract" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetAbstract" xlink:title="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetAbstract" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" xlink:title="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationAcquiredReceivablesFairValue" xlink:label="BusinessCombinationAcquiredReceivablesFairValue" xlink:title="BusinessCombinationAcquiredReceivablesFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationAcquiredReceivablesFairValue" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationAcquiredReceivablesFairValue" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory" xlink:title="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssetsCurrent" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssetsCurrent" xlink:title="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssetsCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssetsCurrent" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssetsCurrent" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther" xlink:title="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:title="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles" xlink:title="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets" xlink:title="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable" xlink:title="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilitiesNoncurrent" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilitiesNoncurrent" xlink:title="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilitiesNoncurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilitiesNoncurrent" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilitiesNoncurrent" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther" xlink:title="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" xlink:title="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue" xlink:label="BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue" xlink:title="BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterest" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterest" xlink:title="BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterest" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterest" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterest" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionEquityInterestIssuedOrIssuableValueAssigned" xlink:label="BusinessAcquisitionEquityInterestIssuedOrIssuableValueAssigned" xlink:title="BusinessAcquisitionEquityInterestIssuedOrIssuableValueAssigned" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessAcquisitionEquityInterestIssuedOrIssuableValueAssigned" xlink:title="definition: BusinessAcquisitionLineItems to BusinessAcquisitionEquityInterestIssuedOrIssuableValueAssigned" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationBargainPurchaseGainRecognizedAmount" xlink:label="BusinessCombinationBargainPurchaseGainRecognizedAmount" xlink:title="BusinessCombinationBargainPurchaseGainRecognizedAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationBargainPurchaseGainRecognizedAmount" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationBargainPurchaseGainRecognizedAmount" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationAcquiredReceivablesGrossContractualAmount" xlink:label="BusinessCombinationAcquiredReceivablesGrossContractualAmount" xlink:title="BusinessCombinationAcquiredReceivablesGrossContractualAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationAcquiredReceivablesGrossContractualAmount" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationAcquiredReceivablesGrossContractualAmount" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationAcquiredReceivablesEstimatedUncollectible" xlink:label="BusinessCombinationAcquiredReceivablesEstimatedUncollectible" xlink:title="BusinessCombinationAcquiredReceivablesEstimatedUncollectible" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationAcquiredReceivablesEstimatedUncollectible" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationAcquiredReceivablesEstimatedUncollectible" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:title="ScheduleOfBusinessAcquisitionsByAcquisitionTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="BusinessAcquisitionLineItems" xlink:to="ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:title="definition: BusinessAcquisitionLineItems to ScheduleOfBusinessAcquisitionsByAcquisitionTable" order="20.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="BusinessAcquisitionAxis" xlink:title="BusinessAcquisitionAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="BusinessAcquisitionAxis" xlink:title="definition: ScheduleOfBusinessAcquisitionsByAcquisitionTable to BusinessAcquisitionAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain_2" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain_2" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_PhotronicsDnpMaskCorporationPdmcMember" xlink:label="PhotronicsDnpMaskCorporationPdmcMember" xlink:title="PhotronicsDnpMaskCorporationPdmcMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="PhotronicsDnpMaskCorporationPdmcMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to PhotronicsDnpMaskCorporationPdmcMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/AcquisitionOfDnpPhotomaskTechnologyTaiwanCoLtdProFormaInformationDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="BusinessAcquisitionLineItems" xlink:title="BusinessAcquisitionLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionProFormaInformationAbstract" xlink:label="BusinessAcquisitionProFormaInformationAbstract" xlink:title="BusinessAcquisitionProFormaInformationAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessAcquisitionProFormaInformationAbstract" xlink:title="definition: BusinessAcquisitionLineItems to BusinessAcquisitionProFormaInformationAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionsProFormaRevenue" xlink:label="BusinessAcquisitionsProFormaRevenue" xlink:title="BusinessAcquisitionsProFormaRevenue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessAcquisitionsProFormaRevenue" xlink:title="definition: BusinessAcquisitionLineItems to BusinessAcquisitionsProFormaRevenue" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss" xlink:label="BusinessAcquisitionsProFormaNetIncomeLoss" xlink:title="BusinessAcquisitionsProFormaNetIncomeLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessAcquisitionsProFormaNetIncomeLoss" xlink:title="definition: BusinessAcquisitionLineItems to BusinessAcquisitionsProFormaNetIncomeLoss" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="NetIncomeLoss" xlink:title="NetIncomeLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="NetIncomeLoss" xlink:title="definition: BusinessAcquisitionLineItems to NetIncomeLoss" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionProFormaEarningsPerShareDiluted" xlink:label="BusinessAcquisitionProFormaEarningsPerShareDiluted" xlink:title="BusinessAcquisitionProFormaEarningsPerShareDiluted" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessAcquisitionProFormaEarningsPerShareDiluted" xlink:title="definition: BusinessAcquisitionLineItems to BusinessAcquisitionProFormaEarningsPerShareDiluted" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:title="ScheduleOfBusinessAcquisitionsByAcquisitionTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="BusinessAcquisitionLineItems" xlink:to="ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:title="definition: BusinessAcquisitionLineItems to ScheduleOfBusinessAcquisitionsByAcquisitionTable" order="6.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="StatementScenarioAxis" xlink:title="StatementScenarioAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="StatementScenarioAxis" xlink:title="definition: ScheduleOfBusinessAcquisitionsByAcquisitionTable to StatementScenarioAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="ScenarioUnspecifiedDomain" xlink:title="ScenarioUnspecifiedDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementScenarioAxis" xlink:to="ScenarioUnspecifiedDomain" xlink:title="definition: StatementScenarioAxis to ScenarioUnspecifiedDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="ScenarioUnspecifiedDomain_2" xlink:title="ScenarioUnspecifiedDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementScenarioAxis" xlink:to="ScenarioUnspecifiedDomain_2" xlink:title="definition: StatementScenarioAxis to ScenarioUnspecifiedDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProFormaMember" xlink:label="ProFormaMember" xlink:title="ProFormaMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScenarioUnspecifiedDomain" xlink:to="ProFormaMember" xlink:title="definition: ScenarioUnspecifiedDomain to ProFormaMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/PropertyPlantAndEquipmentDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="PropertyPlantAndEquipmentLineItems" xlink:title="PropertyPlantAndEquipmentLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNetByTypeAbstract" xlink:label="PropertyPlantAndEquipmentNetByTypeAbstract" xlink:title="PropertyPlantAndEquipmentNetByTypeAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="PropertyPlantAndEquipmentNetByTypeAbstract" xlink:title="definition: PropertyPlantAndEquipmentLineItems to PropertyPlantAndEquipmentNetByTypeAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CapitalLeasesBalanceSheetAssetsByMajorClassNetLesseeBalanceSheetAbstract" xlink:label="CapitalLeasesBalanceSheetAssetsByMajorClassNetLesseeBalanceSheetAbstract" xlink:title="CapitalLeasesBalanceSheetAssetsByMajorClassNetLesseeBalanceSheetAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="CapitalLeasesBalanceSheetAssetsByMajorClassNetLesseeBalanceSheetAbstract" xlink:title="definition: PropertyPlantAndEquipmentLineItems to CapitalLeasesBalanceSheetAssetsByMajorClassNetLesseeBalanceSheetAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CapitalLeasedAssetsGross" xlink:label="CapitalLeasedAssetsGross" xlink:title="CapitalLeasedAssetsGross" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="CapitalLeasedAssetsGross" xlink:title="definition: PropertyPlantAndEquipmentLineItems to CapitalLeasedAssetsGross" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CapitalLeasesLesseeBalanceSheetAssetsByMajorClassAccumulatedDeprecation" xlink:label="CapitalLeasesLesseeBalanceSheetAssetsByMajorClassAccumulatedDeprecation" xlink:title="CapitalLeasesLesseeBalanceSheetAssetsByMajorClassAccumulatedDeprecation" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="CapitalLeasesLesseeBalanceSheetAssetsByMajorClassAccumulatedDeprecation" xlink:title="definition: PropertyPlantAndEquipmentLineItems to CapitalLeasesLesseeBalanceSheetAssetsByMajorClassAccumulatedDeprecation" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CapitalLeasesBalanceSheetAssetsByMajorClassNet" xlink:label="CapitalLeasesBalanceSheetAssetsByMajorClassNet" xlink:title="CapitalLeasesBalanceSheetAssetsByMajorClassNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="CapitalLeasesBalanceSheetAssetsByMajorClassNet" xlink:title="definition: PropertyPlantAndEquipmentLineItems to CapitalLeasesBalanceSheetAssetsByMajorClassNet" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="PropertyPlantAndEquipmentGross" xlink:title="PropertyPlantAndEquipmentGross" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="PropertyPlantAndEquipmentGross" xlink:title="definition: PropertyPlantAndEquipmentLineItems to PropertyPlantAndEquipmentGross" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:title="AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:title="definition: PropertyPlantAndEquipmentLineItems to AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="PropertyPlantAndEquipmentNet" xlink:title="PropertyPlantAndEquipmentNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="PropertyPlantAndEquipmentNet" xlink:title="definition: PropertyPlantAndEquipmentLineItems to PropertyPlantAndEquipmentNet" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="ScheduleOfPropertyPlantAndEquipmentTable" xlink:title="ScheduleOfPropertyPlantAndEquipmentTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="ScheduleOfPropertyPlantAndEquipmentTable" xlink:title="definition: PropertyPlantAndEquipmentLineItems to ScheduleOfPropertyPlantAndEquipmentTable" order="9.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="PropertyPlantAndEquipmentByTypeAxis" xlink:title="PropertyPlantAndEquipmentByTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfPropertyPlantAndEquipmentTable" xlink:to="PropertyPlantAndEquipmentByTypeAxis" xlink:title="definition: ScheduleOfPropertyPlantAndEquipmentTable to PropertyPlantAndEquipmentByTypeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="PropertyPlantAndEquipmentTypeDomain" xlink:title="PropertyPlantAndEquipmentTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="PropertyPlantAndEquipmentByTypeAxis" xlink:to="PropertyPlantAndEquipmentTypeDomain" xlink:title="definition: PropertyPlantAndEquipmentByTypeAxis to PropertyPlantAndEquipmentTypeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="PropertyPlantAndEquipmentTypeDomain_2" xlink:title="PropertyPlantAndEquipmentTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="PropertyPlantAndEquipmentByTypeAxis" xlink:to="PropertyPlantAndEquipmentTypeDomain_2" xlink:title="definition: PropertyPlantAndEquipmentByTypeAxis to PropertyPlantAndEquipmentTypeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LandMember" xlink:label="LandMember" xlink:title="LandMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="LandMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to LandMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BuildingAndBuildingImprovementsMember" xlink:label="BuildingAndBuildingImprovementsMember" xlink:title="BuildingAndBuildingImprovementsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="BuildingAndBuildingImprovementsMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to BuildingAndBuildingImprovementsMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MachineryAndEquipmentMember" xlink:label="MachineryAndEquipmentMember" xlink:title="MachineryAndEquipmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="MachineryAndEquipmentMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to MachineryAndEquipmentMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LeaseholdImprovementsMember" xlink:label="LeaseholdImprovementsMember" xlink:title="LeaseholdImprovementsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="LeaseholdImprovementsMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to LeaseholdImprovementsMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FurnitureAndFixturesMember" xlink:label="FurnitureAndFixturesMember" xlink:title="FurnitureAndFixturesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="FurnitureAndFixturesMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to FurnitureAndFixturesMember" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConstructionInProgressMember" xlink:label="ConstructionInProgressMember" xlink:title="ConstructionInProgressMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="ConstructionInProgressMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to ConstructionInProgressMember" order="6.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/IntangibleAssetsDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:label="FiniteLivedIntangibleAssetsLineItems" xlink:title="FiniteLivedIntangibleAssetsLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="AmortizationOfIntangibleAssets" xlink:title="AmortizationOfIntangibleAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="AmortizationOfIntangibleAssets" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to AmortizationOfIntangibleAssets" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" xlink:label="AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" xlink:title="AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNetAbstract" xlink:label="FiniteLivedIntangibleAssetsNetAbstract" xlink:title="FiniteLivedIntangibleAssetsNetAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetsNetAbstract" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetsNetAbstract" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:label="FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:title="FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:label="FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:title="FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:label="FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:title="FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:label="FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:title="FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:label="FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:title="FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:label="FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:title="FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:label="FiniteLivedIntangibleAssetsGross" xlink:title="FiniteLivedIntangibleAssetsGross" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetsGross" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetsGross" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:title="FiniteLivedIntangibleAssetsAccumulatedAmortization" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetsAccumulatedAmortization" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="FiniteLivedIntangibleAssetsNet" xlink:title="FiniteLivedIntangibleAssetsNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetsNet" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetsNet" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:label="ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:title="ScheduleOfFiniteLivedIntangibleAssetsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to ScheduleOfFiniteLivedIntangibleAssetsTable" order="13.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:title="FiniteLivedIntangibleAssetsByMajorClassAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:to="FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:title="definition: ScheduleOfFiniteLivedIntangibleAssetsTable to FiniteLivedIntangibleAssetsByMajorClassAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:title="FiniteLivedIntangibleAssetsMajorClassNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:title="definition: FiniteLivedIntangibleAssetsByMajorClassAxis to FiniteLivedIntangibleAssetsMajorClassNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="FiniteLivedIntangibleAssetsMajorClassNameDomain_2" xlink:title="FiniteLivedIntangibleAssetsMajorClassNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="FiniteLivedIntangibleAssetsMajorClassNameDomain_2" xlink:title="definition: FiniteLivedIntangibleAssetsByMajorClassAxis to FiniteLivedIntangibleAssetsMajorClassNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LicensingAgreementsMember" xlink:label="LicensingAgreementsMember" xlink:title="LicensingAgreementsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="LicensingAgreementsMember" xlink:title="definition: FiniteLivedIntangibleAssetsMajorClassNameDomain to LicensingAgreementsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CustomerListsMember" xlink:label="CustomerListsMember" xlink:title="CustomerListsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="CustomerListsMember" xlink:title="definition: FiniteLivedIntangibleAssetsMajorClassNameDomain to CustomerListsMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_SupplyAgreementMember" xlink:label="SupplyAgreementMember" xlink:title="SupplyAgreementMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="SupplyAgreementMember" xlink:title="definition: FiniteLivedIntangibleAssetsMajorClassNameDomain to SupplyAgreementMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ComputerSoftwareIntangibleAssetMember" xlink:label="ComputerSoftwareIntangibleAssetMember" xlink:title="ComputerSoftwareIntangibleAssetMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="ComputerSoftwareIntangibleAssetMember" xlink:title="definition: FiniteLivedIntangibleAssetsMajorClassNameDomain to ComputerSoftwareIntangibleAssetMember" order="4.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/JointVentureTechnologyLicenseAndOtherAgreementsWithMicronTechnologyIncDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_VariableInterestEntityLineItems" xlink:label="VariableInterestEntityLineItems" xlink:title="VariableInterestEntityLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_VariableInterestEntityMethodologyForDeterminingWhetherEnterpriseIsPrimaryBeneficiary" xlink:label="VariableInterestEntityMethodologyForDeterminingWhetherEnterpriseIsPrimaryBeneficiary" xlink:title="VariableInterestEntityMethodologyForDeterminingWhetherEnterpriseIsPrimaryBeneficiary" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="VariableInterestEntityMethodologyForDeterminingWhetherEnterpriseIsPrimaryBeneficiary" xlink:title="definition: VariableInterestEntityLineItems to VariableInterestEntityMethodologyForDeterminingWhetherEnterpriseIsPrimaryBeneficiary" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_InvestmentsInAndAdvancesToAffiliatesAtFairValuePeriodIncreaseDecrease" xlink:label="InvestmentsInAndAdvancesToAffiliatesAtFairValuePeriodIncreaseDecrease" xlink:title="InvestmentsInAndAdvancesToAffiliatesAtFairValuePeriodIncreaseDecrease" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="InvestmentsInAndAdvancesToAffiliatesAtFairValuePeriodIncreaseDecrease" xlink:title="definition: VariableInterestEntityLineItems to InvestmentsInAndAdvancesToAffiliatesAtFairValuePeriodIncreaseDecrease" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EquityMethodInvestmentDividendsOrDistributions" xlink:label="EquityMethodInvestmentDividendsOrDistributions" xlink:title="EquityMethodInvestmentDividendsOrDistributions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="EquityMethodInvestmentDividendsOrDistributions" xlink:title="definition: VariableInterestEntityLineItems to EquityMethodInvestmentDividendsOrDistributions" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount" xlink:label="VariableInterestEntityEntityMaximumLossExposureAmount" xlink:title="VariableInterestEntityEntityMaximumLossExposureAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="VariableInterestEntityEntityMaximumLossExposureAmount" xlink:title="definition: VariableInterestEntityLineItems to VariableInterestEntityEntityMaximumLossExposureAmount" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_VariableInterestEntityActivityBetweenVIEAndEntityOperatingIncomeOrLoss" xlink:label="VariableInterestEntityActivityBetweenVIEAndEntityOperatingIncomeOrLoss" xlink:title="VariableInterestEntityActivityBetweenVIEAndEntityOperatingIncomeOrLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="VariableInterestEntityActivityBetweenVIEAndEntityOperatingIncomeOrLoss" xlink:title="definition: VariableInterestEntityLineItems to VariableInterestEntityActivityBetweenVIEAndEntityOperatingIncomeOrLoss" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DueToRelatedPartiesCurrent" xlink:label="DueToRelatedPartiesCurrent" xlink:title="DueToRelatedPartiesCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="DueToRelatedPartiesCurrent" xlink:title="definition: VariableInterestEntityLineItems to DueToRelatedPartiesCurrent" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="AccountsReceivableNetCurrent" xlink:title="AccountsReceivableNetCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="AccountsReceivableNetCurrent" xlink:title="definition: VariableInterestEntityLineItems to AccountsReceivableNetCurrent" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FeesAndCommissionsOther" xlink:label="FeesAndCommissionsOther" xlink:title="FeesAndCommissionsOther" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="FeesAndCommissionsOther" xlink:title="definition: VariableInterestEntityLineItems to FeesAndCommissionsOther" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="AmortizationOfIntangibleAssets" xlink:title="AmortizationOfIntangibleAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="AmortizationOfIntangibleAssets" xlink:title="definition: VariableInterestEntityLineItems to AmortizationOfIntangibleAssets" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CostOfGoodsSold" xlink:label="CostOfGoodsSold" xlink:title="CostOfGoodsSold" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="CostOfGoodsSold" xlink:title="definition: VariableInterestEntityLineItems to CostOfGoodsSold" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="ResearchAndDevelopmentExpense" xlink:title="ResearchAndDevelopmentExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="ResearchAndDevelopmentExpense" xlink:title="definition: VariableInterestEntityLineItems to ResearchAndDevelopmentExpense" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PaymentsToAcquireProductiveAssets" xlink:label="PaymentsToAcquireProductiveAssets" xlink:title="PaymentsToAcquireProductiveAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="PaymentsToAcquireProductiveAssets" xlink:title="definition: VariableInterestEntityLineItems to PaymentsToAcquireProductiveAssets" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProceedsFromSaleOfEquityMethodInvestments" xlink:label="ProceedsFromSaleOfEquityMethodInvestments" xlink:title="ProceedsFromSaleOfEquityMethodInvestments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="ProceedsFromSaleOfEquityMethodInvestments" xlink:title="definition: VariableInterestEntityLineItems to ProceedsFromSaleOfEquityMethodInvestments" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EquityMethodInvestmentRealizedGainLossOnDisposal" xlink:label="EquityMethodInvestmentRealizedGainLossOnDisposal" xlink:title="EquityMethodInvestmentRealizedGainLossOnDisposal" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="EquityMethodInvestmentRealizedGainLossOnDisposal" xlink:title="definition: VariableInterestEntityLineItems to EquityMethodInvestmentRealizedGainLossOnDisposal" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_SupplyAgreementTermSubjectToMutuallyAgreeableRenewals" xlink:label="SupplyAgreementTermSubjectToMutuallyAgreeableRenewals" xlink:title="SupplyAgreementTermSubjectToMutuallyAgreeableRenewals" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="SupplyAgreementTermSubjectToMutuallyAgreeableRenewals" xlink:title="definition: VariableInterestEntityLineItems to SupplyAgreementTermSubjectToMutuallyAgreeableRenewals" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationAbstract" xlink:label="EquityMethodInvestmentSummarizedFinancialInformationAbstract" xlink:title="EquityMethodInvestmentSummarizedFinancialInformationAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="EquityMethodInvestmentSummarizedFinancialInformationAbstract" xlink:title="definition: VariableInterestEntityLineItems to EquityMethodInvestmentSummarizedFinancialInformationAbstract" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationCurrentAssets" xlink:label="EquityMethodInvestmentSummarizedFinancialInformationCurrentAssets" xlink:title="EquityMethodInvestmentSummarizedFinancialInformationCurrentAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="EquityMethodInvestmentSummarizedFinancialInformationCurrentAssets" xlink:title="definition: VariableInterestEntityLineItems to EquityMethodInvestmentSummarizedFinancialInformationCurrentAssets" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNoncurrentAssets" xlink:label="EquityMethodInvestmentSummarizedFinancialInformationNoncurrentAssets" xlink:title="EquityMethodInvestmentSummarizedFinancialInformationNoncurrentAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="EquityMethodInvestmentSummarizedFinancialInformationNoncurrentAssets" xlink:title="definition: VariableInterestEntityLineItems to EquityMethodInvestmentSummarizedFinancialInformationNoncurrentAssets" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationCurrentLiabilities" xlink:label="EquityMethodInvestmentSummarizedFinancialInformationCurrentLiabilities" xlink:title="EquityMethodInvestmentSummarizedFinancialInformationCurrentLiabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="EquityMethodInvestmentSummarizedFinancialInformationCurrentLiabilities" xlink:title="definition: VariableInterestEntityLineItems to EquityMethodInvestmentSummarizedFinancialInformationCurrentLiabilities" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNoncurrentLiabilities" xlink:label="EquityMethodInvestmentSummarizedFinancialInformationNoncurrentLiabilities" xlink:title="EquityMethodInvestmentSummarizedFinancialInformationNoncurrentLiabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="EquityMethodInvestmentSummarizedFinancialInformationNoncurrentLiabilities" xlink:title="definition: VariableInterestEntityLineItems to EquityMethodInvestmentSummarizedFinancialInformationNoncurrentLiabilities" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationRevenue" xlink:label="EquityMethodInvestmentSummarizedFinancialInformationRevenue" xlink:title="EquityMethodInvestmentSummarizedFinancialInformationRevenue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="EquityMethodInvestmentSummarizedFinancialInformationRevenue" xlink:title="definition: VariableInterestEntityLineItems to EquityMethodInvestmentSummarizedFinancialInformationRevenue" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationGrossProfitLoss" xlink:label="EquityMethodInvestmentSummarizedFinancialInformationGrossProfitLoss" xlink:title="EquityMethodInvestmentSummarizedFinancialInformationGrossProfitLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="EquityMethodInvestmentSummarizedFinancialInformationGrossProfitLoss" xlink:title="definition: VariableInterestEntityLineItems to EquityMethodInvestmentSummarizedFinancialInformationGrossProfitLoss" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNetIncomeLoss" xlink:label="EquityMethodInvestmentSummarizedFinancialInformationNetIncomeLoss" xlink:title="EquityMethodInvestmentSummarizedFinancialInformationNetIncomeLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="EquityMethodInvestmentSummarizedFinancialInformationNetIncomeLoss" xlink:title="definition: VariableInterestEntityLineItems to EquityMethodInvestmentSummarizedFinancialInformationNetIncomeLoss" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfVariableInterestEntitiesTable" xlink:label="ScheduleOfVariableInterestEntitiesTable" xlink:title="ScheduleOfVariableInterestEntitiesTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="VariableInterestEntityLineItems" xlink:to="ScheduleOfVariableInterestEntitiesTable" xlink:title="definition: VariableInterestEntityLineItems to ScheduleOfVariableInterestEntitiesTable" order="24.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis" xlink:label="VariableInterestEntitiesByClassificationOfEntityAxis" xlink:title="VariableInterestEntitiesByClassificationOfEntityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfVariableInterestEntitiesTable" xlink:to="VariableInterestEntitiesByClassificationOfEntityAxis" xlink:title="definition: ScheduleOfVariableInterestEntitiesTable to VariableInterestEntitiesByClassificationOfEntityAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ClassificationOfVariableInterestEntityDomain" xlink:label="ClassificationOfVariableInterestEntityDomain" xlink:title="ClassificationOfVariableInterestEntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="VariableInterestEntitiesByClassificationOfEntityAxis" xlink:to="ClassificationOfVariableInterestEntityDomain" xlink:title="definition: VariableInterestEntitiesByClassificationOfEntityAxis to ClassificationOfVariableInterestEntityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ClassificationOfVariableInterestEntityDomain" xlink:label="ClassificationOfVariableInterestEntityDomain_2" xlink:title="ClassificationOfVariableInterestEntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="VariableInterestEntitiesByClassificationOfEntityAxis" xlink:to="ClassificationOfVariableInterestEntityDomain_2" xlink:title="definition: VariableInterestEntitiesByClassificationOfEntityAxis to ClassificationOfVariableInterestEntityDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_MPMaskMember" xlink:label="MPMaskMember" xlink:title="MPMaskMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassificationOfVariableInterestEntityDomain" xlink:to="MPMaskMember" xlink:title="definition: ClassificationOfVariableInterestEntityDomain to MPMaskMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CoVenturerMember" xlink:label="CoVenturerMember" xlink:title="CoVenturerMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassificationOfVariableInterestEntityDomain" xlink:to="CoVenturerMember" xlink:title="definition: ClassificationOfVariableInterestEntityDomain to CoVenturerMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/AccruedLiabilitiesDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/LongtermBorrowingsDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="DebtInstrumentLineItems" xlink:title="DebtInstrumentLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturitiesAbstract" xlink:label="LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturitiesAbstract" xlink:title="LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturitiesAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturitiesAbstract" xlink:title="definition: DebtInstrumentLineItems to LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturitiesAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="DebtInstrumentInterestRateStatedPercentage" xlink:title="DebtInstrumentInterestRateStatedPercentage" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentInterestRateStatedPercentage" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentInterestRateStatedPercentage" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentMaturityDate" xlink:label="DebtInstrumentMaturityDate" xlink:title="DebtInstrumentMaturityDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentMaturityDate" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentMaturityDate" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepaymentsOfConvertibleDebt" xlink:label="RepaymentsOfConvertibleDebt" xlink:title="RepaymentsOfConvertibleDebt" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="RepaymentsOfConvertibleDebt" xlink:title="definition: DebtInstrumentLineItems to RepaymentsOfConvertibleDebt" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtConversionConvertedInstrumentSharesIssued1" xlink:label="DebtConversionConvertedInstrumentSharesIssued1" xlink:title="DebtConversionConvertedInstrumentSharesIssued1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtConversionConvertedInstrumentSharesIssued1" xlink:title="definition: DebtInstrumentLineItems to DebtConversionConvertedInstrumentSharesIssued1" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentConvertibleNumberOfEquityInstruments" xlink:label="DebtInstrumentConvertibleNumberOfEquityInstruments" xlink:title="DebtInstrumentConvertibleNumberOfEquityInstruments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentConvertibleNumberOfEquityInstruments" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentConvertibleNumberOfEquityInstruments" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_FaceAmountOfEachNoteConvertedOrConvertible" xlink:label="FaceAmountOfEachNoteConvertedOrConvertible" xlink:title="FaceAmountOfEachNoteConvertedOrConvertible" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="FaceAmountOfEachNoteConvertedOrConvertible" xlink:title="definition: DebtInstrumentLineItems to FaceAmountOfEachNoteConvertedOrConvertible" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentConvertibleConversionPrice1" xlink:label="DebtInstrumentConvertibleConversionPrice1" xlink:title="DebtInstrumentConvertibleConversionPrice1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentConvertibleConversionPrice1" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentConvertibleConversionPrice1" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage" xlink:label="DebtInstrumentInterestRateEffectivePercentage" xlink:title="DebtInstrumentInterestRateEffectivePercentage" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentInterestRateEffectivePercentage" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentInterestRateEffectivePercentage" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="DebtInstrumentFaceAmount" xlink:title="DebtInstrumentFaceAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentFaceAmount" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentFaceAmount" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentPeriodicPaymentPrincipal" xlink:label="DebtInstrumentPeriodicPaymentPrincipal" xlink:title="DebtInstrumentPeriodicPaymentPrincipal" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentPeriodicPaymentPrincipal" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentPeriodicPaymentPrincipal" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentFrequencyOfPeriodicPayment" xlink:label="DebtInstrumentFrequencyOfPeriodicPayment" xlink:title="DebtInstrumentFrequencyOfPeriodicPayment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentFrequencyOfPeriodicPayment" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentFrequencyOfPeriodicPayment" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="LineOfCreditFacilityMaximumBorrowingCapacity" xlink:title="LineOfCreditFacilityMaximumBorrowingCapacity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LineOfCreditFacilityMaximumBorrowingCapacity" xlink:title="definition: DebtInstrumentLineItems to LineOfCreditFacilityMaximumBorrowingCapacity" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity" xlink:label="LineOfCreditFacilityCurrentBorrowingCapacity" xlink:title="LineOfCreditFacilityCurrentBorrowingCapacity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LineOfCreditFacilityCurrentBorrowingCapacity" xlink:title="definition: DebtInstrumentLineItems to LineOfCreditFacilityCurrentBorrowingCapacity" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity" xlink:label="LineOfCreditFacilityRemainingBorrowingCapacity" xlink:title="LineOfCreditFacilityRemainingBorrowingCapacity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LineOfCreditFacilityRemainingBorrowingCapacity" xlink:title="definition: DebtInstrumentLineItems to LineOfCreditFacilityRemainingBorrowingCapacity" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LineOfCredit" xlink:label="LineOfCredit" xlink:title="LineOfCredit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LineOfCredit" xlink:title="definition: DebtInstrumentLineItems to LineOfCredit" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentTerm" xlink:label="DebtInstrumentTerm" xlink:title="DebtInstrumentTerm" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentTerm" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentTerm" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsNetMinimumPayments1" xlink:label="CapitalLeasesFutureMinimumPaymentsNetMinimumPayments1" xlink:title="CapitalLeasesFutureMinimumPaymentsNetMinimumPayments1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="CapitalLeasesFutureMinimumPaymentsNetMinimumPayments1" xlink:title="definition: DebtInstrumentLineItems to CapitalLeasesFutureMinimumPaymentsNetMinimumPayments1" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_InterestPaid" xlink:label="InterestPaid" xlink:title="InterestPaid" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="InterestPaid" xlink:title="definition: DebtInstrumentLineItems to InterestPaid" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PaymentsOfFinancingCosts" xlink:label="PaymentsOfFinancingCosts" xlink:title="PaymentsOfFinancingCosts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="PaymentsOfFinancingCosts" xlink:title="definition: DebtInstrumentLineItems to PaymentsOfFinancingCosts" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDueAbstract" xlink:label="CapitalLeasesFutureMinimumPaymentsDueAbstract" xlink:title="CapitalLeasesFutureMinimumPaymentsDueAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="CapitalLeasesFutureMinimumPaymentsDueAbstract" xlink:title="definition: DebtInstrumentLineItems to CapitalLeasesFutureMinimumPaymentsDueAbstract" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDueCurrent" xlink:label="CapitalLeasesFutureMinimumPaymentsDueCurrent" xlink:title="CapitalLeasesFutureMinimumPaymentsDueCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="CapitalLeasesFutureMinimumPaymentsDueCurrent" xlink:title="definition: DebtInstrumentLineItems to CapitalLeasesFutureMinimumPaymentsDueCurrent" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears" xlink:label="CapitalLeasesFutureMinimumPaymentsDueInTwoYears" xlink:title="CapitalLeasesFutureMinimumPaymentsDueInTwoYears" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="CapitalLeasesFutureMinimumPaymentsDueInTwoYears" xlink:title="definition: DebtInstrumentLineItems to CapitalLeasesFutureMinimumPaymentsDueInTwoYears" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDue" xlink:label="CapitalLeasesFutureMinimumPaymentsDue" xlink:title="CapitalLeasesFutureMinimumPaymentsDue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="CapitalLeasesFutureMinimumPaymentsDue" xlink:title="definition: DebtInstrumentLineItems to CapitalLeasesFutureMinimumPaymentsDue" order="24.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsInterestIncludedInPayments" xlink:label="CapitalLeasesFutureMinimumPaymentsInterestIncludedInPayments" xlink:title="CapitalLeasesFutureMinimumPaymentsInterestIncludedInPayments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="CapitalLeasesFutureMinimumPaymentsInterestIncludedInPayments" xlink:title="definition: DebtInstrumentLineItems to CapitalLeasesFutureMinimumPaymentsInterestIncludedInPayments" order="25.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CapitalLeaseObligations" xlink:label="CapitalLeaseObligations" xlink:title="CapitalLeaseObligations" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="CapitalLeaseObligations" xlink:title="definition: DebtInstrumentLineItems to CapitalLeaseObligations" order="26.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CapitalLeaseObligationsCurrent" xlink:label="CapitalLeaseObligationsCurrent" xlink:title="CapitalLeaseObligationsCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="CapitalLeaseObligationsCurrent" xlink:title="definition: DebtInstrumentLineItems to CapitalLeaseObligationsCurrent" order="27.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CapitalLeaseObligationsNoncurrent" xlink:label="CapitalLeaseObligationsNoncurrent" xlink:title="CapitalLeaseObligationsNoncurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="CapitalLeaseObligationsNoncurrent" xlink:title="definition: DebtInstrumentLineItems to CapitalLeaseObligationsNoncurrent" order="28.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities" xlink:label="LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities" xlink:title="LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities" xlink:title="definition: DebtInstrumentLineItems to LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities" order="29.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConvertibleDebt" xlink:label="ConvertibleDebt" xlink:title="ConvertibleDebt" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="ConvertibleDebt" xlink:title="definition: DebtInstrumentLineItems to ConvertibleDebt" order="30.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent" xlink:label="LongTermDebtAndCapitalLeaseObligationsCurrent" xlink:title="LongTermDebtAndCapitalLeaseObligationsCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebtAndCapitalLeaseObligationsCurrent" xlink:title="definition: DebtInstrumentLineItems to LongTermDebtAndCapitalLeaseObligationsCurrent" order="31.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligations" xlink:label="LongTermDebtAndCapitalLeaseObligations" xlink:title="LongTermDebtAndCapitalLeaseObligations" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebtAndCapitalLeaseObligations" xlink:title="definition: DebtInstrumentLineItems to LongTermDebtAndCapitalLeaseObligations" order="32.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="DebtInstrumentTable" xlink:title="DebtInstrumentTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentTable" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentTable" order="33.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="DebtInstrumentAxis" xlink:title="DebtInstrumentAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DebtInstrumentTable" xlink:to="DebtInstrumentAxis" xlink:title="definition: DebtInstrumentTable to DebtInstrumentAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="DebtInstrumentNameDomain" xlink:title="DebtInstrumentNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="DebtInstrumentAxis" xlink:to="DebtInstrumentNameDomain" xlink:title="definition: DebtInstrumentAxis to DebtInstrumentNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="DebtInstrumentNameDomain_2" xlink:title="DebtInstrumentNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="DebtInstrumentAxis" xlink:to="DebtInstrumentNameDomain_2" xlink:title="definition: DebtInstrumentAxis to DebtInstrumentNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_ConvertibleSeniorNotesDueOnApril2019Member" xlink:label="ConvertibleSeniorNotesDueOnApril2019Member" xlink:title="ConvertibleSeniorNotesDueOnApril2019Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="ConvertibleSeniorNotesDueOnApril2019Member" xlink:title="definition: DebtInstrumentNameDomain to ConvertibleSeniorNotesDueOnApril2019Member" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_ConvertibleSeniorNotesDueOnApril2016Member" xlink:label="ConvertibleSeniorNotesDueOnApril2016Member" xlink:title="ConvertibleSeniorNotesDueOnApril2016Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="ConvertibleSeniorNotesDueOnApril2016Member" xlink:title="definition: DebtInstrumentNameDomain to ConvertibleSeniorNotesDueOnApril2016Member" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_CapitalLeaseObligationPayableThrough2018Member" xlink:label="CapitalLeaseObligationPayableThrough2018Member" xlink:title="CapitalLeaseObligationPayableThrough2018Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="CapitalLeaseObligationPayableThrough2018Member" xlink:title="definition: DebtInstrumentNameDomain to CapitalLeaseObligationPayableThrough2018Member" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_CapitalLeaseObligationPayableThrough2016Member" xlink:label="CapitalLeaseObligationPayableThrough2016Member" xlink:title="CapitalLeaseObligationPayableThrough2016Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="CapitalLeaseObligationPayableThrough2016Member" xlink:title="definition: DebtInstrumentNameDomain to CapitalLeaseObligationPayableThrough2016Member" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="CreditFacilityAxis" xlink:title="CreditFacilityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DebtInstrumentTable" xlink:to="CreditFacilityAxis" xlink:title="definition: DebtInstrumentTable to CreditFacilityAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="CreditFacilityDomain" xlink:title="CreditFacilityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="CreditFacilityAxis" xlink:to="CreditFacilityDomain" xlink:title="definition: CreditFacilityAxis to CreditFacilityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="CreditFacilityDomain_2" xlink:title="CreditFacilityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="CreditFacilityAxis" xlink:to="CreditFacilityDomain_2" xlink:title="definition: CreditFacilityAxis to CreditFacilityDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:label="RevolvingCreditFacilityMember" xlink:title="RevolvingCreditFacilityMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CreditFacilityDomain" xlink:to="RevolvingCreditFacilityMember" xlink:title="definition: CreditFacilityDomain to RevolvingCreditFacilityMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/OperatingLeasesDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/SharebasedCompensationDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPlanModificationDescriptionAndTerms" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardPlanModificationDescriptionAndTerms" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardPlanModificationDescriptionAndTerms" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardPlanModificationDescriptionAndTerms" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardPlanModificationDescriptionAndTerms" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="AllocatedShareBasedCompensationExpense" xlink:title="AllocatedShareBasedCompensationExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="AllocatedShareBasedCompensationExpense" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to AllocatedShareBasedCompensationExpense" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount" xlink:label="EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount" xlink:title="EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitRealizedFromExerciseOfStockOptions" xlink:label="EmployeeServiceShareBasedCompensationTaxBenefitRealizedFromExerciseOfStockOptions" xlink:title="EmployeeServiceShareBasedCompensationTaxBenefitRealizedFromExerciseOfStockOptions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="EmployeeServiceShareBasedCompensationTaxBenefitRealizedFromExerciseOfStockOptions" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to EmployeeServiceShareBasedCompensationTaxBenefitRealizedFromExerciseOfStockOptions" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:label="SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:title="SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions" xlink:label="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions" xlink:title="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent" xlink:label="SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent" xlink:title="SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsCumulativeSharesIssued" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsCumulativeSharesIssued" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsCumulativeSharesIssued" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsCumulativeSharesIssued" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsCumulativeSharesIssued" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_StockOptionsActivityAbstract" xlink:label="StockOptionsActivityAbstract" xlink:title="StockOptionsActivityAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="StockOptionsActivityAbstract" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to StockOptionsActivityAbstract" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsThatAreVestedAndExpectedToVestWeightedAverageGrantDateFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsThatAreVestedAndExpectedToVestWeightedAverageGrantDateFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsThatAreVestedAndExpectedToVestWeightedAverageGrantDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsThatAreVestedAndExpectedToVestWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsThatAreVestedAndExpectedToVestWeightedAverageGrantDateFairValue" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" order="24.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" order="25.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedAndExpectedToVest" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedAndExpectedToVest" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedAndExpectedToVest" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedAndExpectedToVest" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedAndExpectedToVest" order="26.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" order="27.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" order="28.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract" order="29.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAggregateIntrinsicValueAbstract" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAggregateIntrinsicValueAbstract" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAggregateIntrinsicValueAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAggregateIntrinsicValueAbstract" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAggregateIntrinsicValueAbstract" order="30.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" order="31.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" order="32.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" order="33.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProceedsFromStockOptionsExercised" xlink:label="ProceedsFromStockOptionsExercised" xlink:title="ProceedsFromStockOptionsExercised" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ProceedsFromStockOptionsExercised" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ProceedsFromStockOptionsExercised" order="34.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" xlink:label="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" xlink:title="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" order="35.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:title="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" order="36.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" order="37.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" xlink:label="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" xlink:title="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" order="38.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue" order="39.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:label="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:title="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" order="40.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" xlink:label="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" xlink:title="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" order="41.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1" xlink:label="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1" xlink:title="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1" order="42.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" order="43.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" order="44.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" order="45.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice" order="46.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" order="47.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice" order="48.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" order="49.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" order="50.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:title="StockIssuedDuringPeriodSharesStockOptionsExercised" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to StockIssuedDuringPeriodSharesStockOptionsExercised" order="51.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod" order="52.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" order="53.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber" order="54.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" order="55.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" order="56.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" order="57.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:label="SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:title="SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" order="58.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="59.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="AwardTypeAxis" xlink:title="AwardTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="AwardTypeAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to AwardTypeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="EmployeeStockOptionMember" xlink:title="EmployeeStockOptionMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="EmployeeStockOptionMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to EmployeeStockOptionMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RestrictedStockMember" xlink:label="RestrictedStockMember" xlink:title="RestrictedStockMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="RestrictedStockMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to RestrictedStockMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EmployeeStockMember" xlink:label="EmployeeStockMember" xlink:title="EmployeeStockMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="EmployeeStockMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to EmployeeStockMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="RangeAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to RangeAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeMember" xlink:label="RangeMember" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeMember" xlink:title="definition: RangeAxis to RangeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeMember" xlink:label="RangeMember_2" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeMember_2" xlink:title="definition: RangeAxis to RangeMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MinimumMember" xlink:label="MinimumMember" xlink:title="MinimumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MinimumMember" xlink:title="definition: RangeMember to MinimumMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MaximumMember" xlink:label="MaximumMember" xlink:title="MaximumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MaximumMember" xlink:title="definition: RangeMember to MaximumMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/EmployeeRetirementPlansDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/IncomeTaxesDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OperatingLossCarryforwardsLineItems" xlink:label="OperatingLossCarryforwardsLineItems" xlink:title="OperatingLossCarryforwardsLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxAssetsNetAbstract" xlink:label="DeferredTaxAssetsNetAbstract" xlink:title="DeferredTaxAssetsNetAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="DeferredTaxAssetsNetAbstract" xlink:title="definition: OperatingLossCarryforwardsLineItems to DeferredTaxAssetsNetAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxUncertaintiesAbstract" xlink:label="IncomeTaxUncertaintiesAbstract" xlink:title="IncomeTaxUncertaintiesAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="IncomeTaxUncertaintiesAbstract" xlink:title="definition: OperatingLossCarryforwardsLineItems to IncomeTaxUncertaintiesAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued" xlink:label="UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued" xlink:title="UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued" xlink:title="definition: OperatingLossCarryforwardsLineItems to UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate" xlink:label="UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate" xlink:title="UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate" xlink:title="definition: OperatingLossCarryforwardsLineItems to UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_UnrecognizedTaxBenefits" xlink:label="UnrecognizedTaxBenefits" xlink:title="UnrecognizedTaxBenefits" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="UnrecognizedTaxBenefits" xlink:title="definition: OperatingLossCarryforwardsLineItems to UnrecognizedTaxBenefits" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxAssetsNetOfValuationAllowanceAbstract" xlink:label="DeferredTaxAssetsNetOfValuationAllowanceAbstract" xlink:title="DeferredTaxAssetsNetOfValuationAllowanceAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="DeferredTaxAssetsNetOfValuationAllowanceAbstract" xlink:title="definition: OperatingLossCarryforwardsLineItems to DeferredTaxAssetsNetOfValuationAllowanceAbstract" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxLiabilitiesAbstract" xlink:label="DeferredTaxLiabilitiesAbstract" xlink:title="DeferredTaxLiabilitiesAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="DeferredTaxLiabilitiesAbstract" xlink:title="definition: OperatingLossCarryforwardsLineItems to DeferredTaxLiabilitiesAbstract" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredIncomeTaxAssetsNet" xlink:label="DeferredIncomeTaxAssetsNet" xlink:title="DeferredIncomeTaxAssetsNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="DeferredIncomeTaxAssetsNet" xlink:title="definition: OperatingLossCarryforwardsLineItems to DeferredIncomeTaxAssetsNet" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxAssetsLiabilitiesNetAbstract" xlink:label="DeferredTaxAssetsLiabilitiesNetAbstract" xlink:title="DeferredTaxAssetsLiabilitiesNetAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="DeferredTaxAssetsLiabilitiesNetAbstract" xlink:title="definition: OperatingLossCarryforwardsLineItems to DeferredTaxAssetsLiabilitiesNetAbstract" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxAssetsNetNoncurrent" xlink:label="DeferredTaxAssetsNetNoncurrent" xlink:title="DeferredTaxAssetsNetNoncurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="DeferredTaxAssetsNetNoncurrent" xlink:title="definition: OperatingLossCarryforwardsLineItems to DeferredTaxAssetsNetNoncurrent" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxLiabilitiesNoncurrent" xlink:label="DeferredTaxLiabilitiesNoncurrent" xlink:title="DeferredTaxLiabilitiesNoncurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="DeferredTaxLiabilitiesNoncurrent" xlink:title="definition: OperatingLossCarryforwardsLineItems to DeferredTaxLiabilitiesNoncurrent" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxLiabilitiesUndistributedForeignEarnings" xlink:label="DeferredTaxLiabilitiesUndistributedForeignEarnings" xlink:title="DeferredTaxLiabilitiesUndistributedForeignEarnings" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="DeferredTaxLiabilitiesUndistributedForeignEarnings" xlink:title="definition: OperatingLossCarryforwardsLineItems to DeferredTaxLiabilitiesUndistributedForeignEarnings" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment" xlink:label="DeferredTaxLiabilitiesPropertyPlantAndEquipment" xlink:title="DeferredTaxLiabilitiesPropertyPlantAndEquipment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="DeferredTaxLiabilitiesPropertyPlantAndEquipment" xlink:title="definition: OperatingLossCarryforwardsLineItems to DeferredTaxLiabilitiesPropertyPlantAndEquipment" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxLiabilitiesInvestments" xlink:label="DeferredTaxLiabilitiesInvestments" xlink:title="DeferredTaxLiabilitiesInvestments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="DeferredTaxLiabilitiesInvestments" xlink:title="definition: OperatingLossCarryforwardsLineItems to DeferredTaxLiabilitiesInvestments" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxLiabilitiesOther" xlink:label="DeferredTaxLiabilitiesOther" xlink:title="DeferredTaxLiabilitiesOther" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="DeferredTaxLiabilitiesOther" xlink:title="definition: OperatingLossCarryforwardsLineItems to DeferredTaxLiabilitiesOther" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredIncomeTaxLiabilities" xlink:label="DeferredIncomeTaxLiabilities" xlink:title="DeferredIncomeTaxLiabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="DeferredIncomeTaxLiabilities" xlink:title="definition: OperatingLossCarryforwardsLineItems to DeferredIncomeTaxLiabilities" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwards" xlink:label="DeferredTaxAssetsOperatingLossCarryforwards" xlink:title="DeferredTaxAssetsOperatingLossCarryforwards" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="DeferredTaxAssetsOperatingLossCarryforwards" xlink:title="definition: OperatingLossCarryforwardsLineItems to DeferredTaxAssetsOperatingLossCarryforwards" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsReserves" xlink:label="DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsReserves" xlink:title="DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsReserves" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsReserves" xlink:title="definition: OperatingLossCarryforwardsLineItems to DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsReserves" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsAlternativeMinimumTax" xlink:label="DeferredTaxAssetsTaxCreditCarryforwardsAlternativeMinimumTax" xlink:title="DeferredTaxAssetsTaxCreditCarryforwardsAlternativeMinimumTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="DeferredTaxAssetsTaxCreditCarryforwardsAlternativeMinimumTax" xlink:title="definition: OperatingLossCarryforwardsLineItems to DeferredTaxAssetsTaxCreditCarryforwardsAlternativeMinimumTax" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsOther" xlink:label="DeferredTaxAssetsTaxCreditCarryforwardsOther" xlink:title="DeferredTaxAssetsTaxCreditCarryforwardsOther" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="DeferredTaxAssetsTaxCreditCarryforwardsOther" xlink:title="definition: OperatingLossCarryforwardsLineItems to DeferredTaxAssetsTaxCreditCarryforwardsOther" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxAssetsOther" xlink:label="DeferredTaxAssetsOther" xlink:title="DeferredTaxAssetsOther" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="DeferredTaxAssetsOther" xlink:title="definition: OperatingLossCarryforwardsLineItems to DeferredTaxAssetsOther" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxAssetsGross" xlink:label="DeferredTaxAssetsGross" xlink:title="DeferredTaxAssetsGross" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="DeferredTaxAssetsGross" xlink:title="definition: OperatingLossCarryforwardsLineItems to DeferredTaxAssetsGross" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxAssetsValuationAllowance" xlink:label="DeferredTaxAssetsValuationAllowance" xlink:title="DeferredTaxAssetsValuationAllowance" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="DeferredTaxAssetsValuationAllowance" xlink:title="definition: OperatingLossCarryforwardsLineItems to DeferredTaxAssetsValuationAllowance" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxAssetsNet" xlink:label="DeferredTaxAssetsNet" xlink:title="DeferredTaxAssetsNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="DeferredTaxAssetsNet" xlink:title="definition: OperatingLossCarryforwardsLineItems to DeferredTaxAssetsNet" order="24.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OperatingLossCarryforwardsTable" xlink:label="OperatingLossCarryforwardsTable" xlink:title="OperatingLossCarryforwardsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="OperatingLossCarryforwardsTable" xlink:title="definition: OperatingLossCarryforwardsLineItems to OperatingLossCarryforwardsTable" order="25.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:label="BalanceSheetLocationAxis" xlink:title="BalanceSheetLocationAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="OperatingLossCarryforwardsTable" xlink:to="BalanceSheetLocationAxis" xlink:title="definition: OperatingLossCarryforwardsTable to BalanceSheetLocationAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="BalanceSheetLocationDomain" xlink:title="BalanceSheetLocationDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BalanceSheetLocationAxis" xlink:to="BalanceSheetLocationDomain" xlink:title="definition: BalanceSheetLocationAxis to BalanceSheetLocationDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="BalanceSheetLocationDomain_2" xlink:title="BalanceSheetLocationDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BalanceSheetLocationAxis" xlink:to="BalanceSheetLocationDomain_2" xlink:title="definition: BalanceSheetLocationAxis to BalanceSheetLocationDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherLiabilitiesMember" xlink:label="OtherLiabilitiesMember" xlink:title="OtherLiabilitiesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BalanceSheetLocationDomain" xlink:to="OtherLiabilitiesMember" xlink:title="definition: BalanceSheetLocationDomain to OtherLiabilitiesMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_AdjustmentOfDeferredTaxAssetMember" xlink:label="AdjustmentOfDeferredTaxAssetMember" xlink:title="AdjustmentOfDeferredTaxAssetMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BalanceSheetLocationDomain" xlink:to="AdjustmentOfDeferredTaxAssetMember" xlink:title="definition: BalanceSheetLocationDomain to AdjustmentOfDeferredTaxAssetMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/IncomeTaxesUnrecognizedTaxBenefitsAndCarryforwardsDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_TaxCreditCarryforwardLineItems" xlink:label="TaxCreditCarryforwardLineItems" xlink:title="TaxCreditCarryforwardLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_TaxCreditCarryforwardAmount" xlink:label="TaxCreditCarryforwardAmount" xlink:title="TaxCreditCarryforwardAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TaxCreditCarryforwardLineItems" xlink:to="TaxCreditCarryforwardAmount" xlink:title="definition: TaxCreditCarryforwardLineItems to TaxCreditCarryforwardAmount" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_TaxCreditCarryforwardExpirationDate" xlink:label="TaxCreditCarryforwardExpirationDate" xlink:title="TaxCreditCarryforwardExpirationDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TaxCreditCarryforwardLineItems" xlink:to="TaxCreditCarryforwardExpirationDate" xlink:title="definition: TaxCreditCarryforwardLineItems to TaxCreditCarryforwardExpirationDate" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_FinancialStatementDeferredIncomeTaxesAbstract" xlink:label="FinancialStatementDeferredIncomeTaxesAbstract" xlink:title="FinancialStatementDeferredIncomeTaxesAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TaxCreditCarryforwardLineItems" xlink:to="FinancialStatementDeferredIncomeTaxesAbstract" xlink:title="definition: TaxCreditCarryforwardLineItems to FinancialStatementDeferredIncomeTaxesAbstract" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxAssetsNetCurrent" xlink:label="DeferredTaxAssetsNetCurrent" xlink:title="DeferredTaxAssetsNetCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TaxCreditCarryforwardLineItems" xlink:to="DeferredTaxAssetsNetCurrent" xlink:title="definition: TaxCreditCarryforwardLineItems to DeferredTaxAssetsNetCurrent" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxAssetsNetNoncurrent" xlink:label="DeferredTaxAssetsNetNoncurrent" xlink:title="DeferredTaxAssetsNetNoncurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TaxCreditCarryforwardLineItems" xlink:to="DeferredTaxAssetsNetNoncurrent" xlink:title="definition: TaxCreditCarryforwardLineItems to DeferredTaxAssetsNetNoncurrent" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxLiabilitiesNoncurrent" xlink:label="DeferredTaxLiabilitiesNoncurrent" xlink:title="DeferredTaxLiabilitiesNoncurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TaxCreditCarryforwardLineItems" xlink:to="DeferredTaxLiabilitiesNoncurrent" xlink:title="definition: TaxCreditCarryforwardLineItems to DeferredTaxLiabilitiesNoncurrent" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_TaxCreditCarryforwardTable" xlink:label="TaxCreditCarryforwardTable" xlink:title="TaxCreditCarryforwardTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="TaxCreditCarryforwardLineItems" xlink:to="TaxCreditCarryforwardTable" xlink:title="definition: TaxCreditCarryforwardLineItems to TaxCreditCarryforwardTable" order="7.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_TaxCreditCarryforwardAxis" xlink:label="TaxCreditCarryforwardAxis" xlink:title="TaxCreditCarryforwardAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="TaxCreditCarryforwardTable" xlink:to="TaxCreditCarryforwardAxis" xlink:title="definition: TaxCreditCarryforwardTable to TaxCreditCarryforwardAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_TaxCreditCarryforwardNameDomain" xlink:label="TaxCreditCarryforwardNameDomain" xlink:title="TaxCreditCarryforwardNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="TaxCreditCarryforwardAxis" xlink:to="TaxCreditCarryforwardNameDomain" xlink:title="definition: TaxCreditCarryforwardAxis to TaxCreditCarryforwardNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_TaxCreditCarryforwardNameDomain" xlink:label="TaxCreditCarryforwardNameDomain_2" xlink:title="TaxCreditCarryforwardNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TaxCreditCarryforwardAxis" xlink:to="TaxCreditCarryforwardNameDomain_2" xlink:title="definition: TaxCreditCarryforwardAxis to TaxCreditCarryforwardNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ForeignCountryMember" xlink:label="ForeignCountryMember" xlink:title="ForeignCountryMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TaxCreditCarryforwardNameDomain" xlink:to="ForeignCountryMember" xlink:title="definition: TaxCreditCarryforwardNameDomain to ForeignCountryMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ResearchMember" xlink:label="ResearchMember" xlink:title="ResearchMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TaxCreditCarryforwardNameDomain" xlink:to="ResearchMember" xlink:title="definition: TaxCreditCarryforwardNameDomain to ResearchMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_AlternateMinimumTaxCreditCarryforwardMember" xlink:label="AlternateMinimumTaxCreditCarryforwardMember" xlink:title="AlternateMinimumTaxCreditCarryforwardMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TaxCreditCarryforwardNameDomain" xlink:to="AlternateMinimumTaxCreditCarryforwardMember" xlink:title="definition: TaxCreditCarryforwardNameDomain to AlternateMinimumTaxCreditCarryforwardMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StateAndLocalJurisdictionMember" xlink:label="StateAndLocalJurisdictionMember" xlink:title="StateAndLocalJurisdictionMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TaxCreditCarryforwardNameDomain" xlink:to="StateAndLocalJurisdictionMember" xlink:title="definition: TaxCreditCarryforwardNameDomain to StateAndLocalJurisdictionMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_InvestmentCreditMember" xlink:label="InvestmentCreditMember" xlink:title="InvestmentCreditMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TaxCreditCarryforwardNameDomain" xlink:to="InvestmentCreditMember" xlink:title="definition: TaxCreditCarryforwardNameDomain to InvestmentCreditMember" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_GeneralBusinessMember" xlink:label="GeneralBusinessMember" xlink:title="GeneralBusinessMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TaxCreditCarryforwardNameDomain" xlink:to="GeneralBusinessMember" xlink:title="definition: TaxCreditCarryforwardNameDomain to GeneralBusinessMember" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:label="AdjustmentsForNewAccountingPronouncementsAxis" xlink:title="AdjustmentsForNewAccountingPronouncementsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="TaxCreditCarryforwardTable" xlink:to="AdjustmentsForNewAccountingPronouncementsAxis" xlink:title="definition: TaxCreditCarryforwardTable to AdjustmentsForNewAccountingPronouncementsAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="TypeOfAdoptionMember" xlink:title="TypeOfAdoptionMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="AdjustmentsForNewAccountingPronouncementsAxis" xlink:to="TypeOfAdoptionMember" xlink:title="definition: AdjustmentsForNewAccountingPronouncementsAxis to TypeOfAdoptionMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="TypeOfAdoptionMember_2" xlink:title="TypeOfAdoptionMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="AdjustmentsForNewAccountingPronouncementsAxis" xlink:to="TypeOfAdoptionMember_2" xlink:title="definition: AdjustmentsForNewAccountingPronouncementsAxis to TypeOfAdoptionMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccountingStandardsUpdate201517Member" xlink:label="AccountingStandardsUpdate201517Member" xlink:title="AccountingStandardsUpdate201517Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TypeOfAdoptionMember" xlink:to="AccountingStandardsUpdate201517Member" xlink:title="definition: TypeOfAdoptionMember to AccountingStandardsUpdate201517Member" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="StatementScenarioAxis" xlink:title="StatementScenarioAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="TaxCreditCarryforwardTable" xlink:to="StatementScenarioAxis" xlink:title="definition: TaxCreditCarryforwardTable to StatementScenarioAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="ScenarioUnspecifiedDomain" xlink:title="ScenarioUnspecifiedDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementScenarioAxis" xlink:to="ScenarioUnspecifiedDomain" xlink:title="definition: StatementScenarioAxis to ScenarioUnspecifiedDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="ScenarioUnspecifiedDomain_2" xlink:title="ScenarioUnspecifiedDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementScenarioAxis" xlink:to="ScenarioUnspecifiedDomain_2" xlink:title="definition: StatementScenarioAxis to ScenarioUnspecifiedDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioPreviouslyReportedMember" xlink:label="ScenarioPreviouslyReportedMember" xlink:title="ScenarioPreviouslyReportedMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScenarioUnspecifiedDomain" xlink:to="ScenarioPreviouslyReportedMember" xlink:title="definition: ScenarioUnspecifiedDomain to ScenarioPreviouslyReportedMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RestatementAdjustmentMember" xlink:label="RestatementAdjustmentMember" xlink:title="RestatementAdjustmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScenarioUnspecifiedDomain" xlink:to="RestatementAdjustmentMember" xlink:title="definition: ScenarioUnspecifiedDomain to RestatementAdjustmentMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_RetrospectivelyAdjustedMember" xlink:label="RetrospectivelyAdjustedMember" xlink:title="RetrospectivelyAdjustedMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScenarioUnspecifiedDomain" xlink:to="RetrospectivelyAdjustedMember" xlink:title="definition: ScenarioUnspecifiedDomain to RetrospectivelyAdjustedMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="TaxCreditCarryforwardTable" xlink:to="RangeAxis" xlink:title="definition: TaxCreditCarryforwardTable to RangeAxis" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeMember" xlink:label="RangeMember" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeMember" xlink:title="definition: RangeAxis to RangeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeMember" xlink:label="RangeMember_2" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeMember_2" xlink:title="definition: RangeAxis to RangeMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MinimumMember" xlink:label="MinimumMember" xlink:title="MinimumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MinimumMember" xlink:title="definition: RangeMember to MinimumMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MaximumMember" xlink:label="MaximumMember" xlink:title="MaximumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MaximumMember" xlink:title="definition: RangeMember to MaximumMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OperatingLossCarryforwardsLineItems" xlink:label="OperatingLossCarryforwardsLineItems" xlink:title="OperatingLossCarryforwardsLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ReconciliationOfUnrecognizedTaxBenefitsExcludingAmountsPertainingToExaminedTaxReturnsRollForward" xlink:label="ReconciliationOfUnrecognizedTaxBenefitsExcludingAmountsPertainingToExaminedTaxReturnsRollForward" xlink:title="ReconciliationOfUnrecognizedTaxBenefitsExcludingAmountsPertainingToExaminedTaxReturnsRollForward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="ReconciliationOfUnrecognizedTaxBenefitsExcludingAmountsPertainingToExaminedTaxReturnsRollForward" xlink:title="definition: OperatingLossCarryforwardsLineItems to ReconciliationOfUnrecognizedTaxBenefitsExcludingAmountsPertainingToExaminedTaxReturnsRollForward" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsComponentsAbstract" xlink:label="DeferredTaxAssetsOperatingLossCarryforwardsComponentsAbstract" xlink:title="DeferredTaxAssetsOperatingLossCarryforwardsComponentsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="DeferredTaxAssetsOperatingLossCarryforwardsComponentsAbstract" xlink:title="definition: OperatingLossCarryforwardsLineItems to DeferredTaxAssetsOperatingLossCarryforwardsComponentsAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ValuationAllowanceAbstract" xlink:label="ValuationAllowanceAbstract" xlink:title="ValuationAllowanceAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="ValuationAllowanceAbstract" xlink:title="definition: OperatingLossCarryforwardsLineItems to ValuationAllowanceAbstract" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_IncomeTaxesAdditionalDisclosuresAbstract" xlink:label="IncomeTaxesAdditionalDisclosuresAbstract" xlink:title="IncomeTaxesAdditionalDisclosuresAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="IncomeTaxesAdditionalDisclosuresAbstract" xlink:title="definition: OperatingLossCarryforwardsLineItems to IncomeTaxesAdditionalDisclosuresAbstract" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_UndistributedEarningsOfForeignSubsidiariesIncludedInConsolidatedRetainedEarnings" xlink:label="UndistributedEarningsOfForeignSubsidiariesIncludedInConsolidatedRetainedEarnings" xlink:title="UndistributedEarningsOfForeignSubsidiariesIncludedInConsolidatedRetainedEarnings" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="UndistributedEarningsOfForeignSubsidiariesIncludedInConsolidatedRetainedEarnings" xlink:title="definition: OperatingLossCarryforwardsLineItems to UndistributedEarningsOfForeignSubsidiariesIncludedInConsolidatedRetainedEarnings" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_EarningsOfForeignSubsidiariesIncludedInConsolidatedRetainedEarningsWhichAreConsideredNotToBePermanentlyReinvested" xlink:label="EarningsOfForeignSubsidiariesIncludedInConsolidatedRetainedEarningsWhichAreConsideredNotToBePermanentlyReinvested" xlink:title="EarningsOfForeignSubsidiariesIncludedInConsolidatedRetainedEarningsWhichAreConsideredNotToBePermanentlyReinvested" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="EarningsOfForeignSubsidiariesIncludedInConsolidatedRetainedEarningsWhichAreConsideredNotToBePermanentlyReinvested" xlink:title="definition: OperatingLossCarryforwardsLineItems to EarningsOfForeignSubsidiariesIncludedInConsolidatedRetainedEarningsWhichAreConsideredNotToBePermanentlyReinvested" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_UndistributedEarningsOfForeignSubsidiaries" xlink:label="UndistributedEarningsOfForeignSubsidiaries" xlink:title="UndistributedEarningsOfForeignSubsidiaries" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="UndistributedEarningsOfForeignSubsidiaries" xlink:title="definition: OperatingLossCarryforwardsLineItems to UndistributedEarningsOfForeignSubsidiaries" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxHolidayAggregateDollarAmount" xlink:label="IncomeTaxHolidayAggregateDollarAmount" xlink:title="IncomeTaxHolidayAggregateDollarAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="IncomeTaxHolidayAggregateDollarAmount" xlink:title="definition: OperatingLossCarryforwardsLineItems to IncomeTaxHolidayAggregateDollarAmount" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxHolidayIncomeTaxBenefitsPerShare" xlink:label="IncomeTaxHolidayIncomeTaxBenefitsPerShare" xlink:title="IncomeTaxHolidayIncomeTaxBenefitsPerShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="IncomeTaxHolidayIncomeTaxBenefitsPerShare" xlink:title="definition: OperatingLossCarryforwardsLineItems to IncomeTaxHolidayIncomeTaxBenefitsPerShare" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_TermOfTaxYearHolidays" xlink:label="TermOfTaxYearHolidays" xlink:title="TermOfTaxYearHolidays" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="TermOfTaxYearHolidays" xlink:title="definition: OperatingLossCarryforwardsLineItems to TermOfTaxYearHolidays" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxHolidayTerminationDate" xlink:label="IncomeTaxHolidayTerminationDate" xlink:title="IncomeTaxHolidayTerminationDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="IncomeTaxHolidayTerminationDate" xlink:title="definition: OperatingLossCarryforwardsLineItems to IncomeTaxHolidayTerminationDate" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxesPaid" xlink:label="IncomeTaxesPaid" xlink:title="IncomeTaxesPaid" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="IncomeTaxesPaid" xlink:title="definition: OperatingLossCarryforwardsLineItems to IncomeTaxesPaid" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProceedsFromIncomeTaxRefunds" xlink:label="ProceedsFromIncomeTaxRefunds" xlink:title="ProceedsFromIncomeTaxRefunds" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="ProceedsFromIncomeTaxRefunds" xlink:title="definition: OperatingLossCarryforwardsLineItems to ProceedsFromIncomeTaxRefunds" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:label="ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:title="ValuationAllowanceDeferredTaxAssetChangeInAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:title="definition: OperatingLossCarryforwardsLineItems to ValuationAllowanceDeferredTaxAssetChangeInAmount" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OperatingLossCarryforwards" xlink:label="OperatingLossCarryforwards" xlink:title="OperatingLossCarryforwards" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="OperatingLossCarryforwards" xlink:title="definition: OperatingLossCarryforwardsLineItems to OperatingLossCarryforwards" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OperatingLossCarryforwardsExpirationDate" xlink:label="OperatingLossCarryforwardsExpirationDate" xlink:title="OperatingLossCarryforwardsExpirationDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="OperatingLossCarryforwardsExpirationDate" xlink:title="definition: OperatingLossCarryforwardsLineItems to OperatingLossCarryforwardsExpirationDate" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_UnrecognizedTaxBenefits" xlink:label="UnrecognizedTaxBenefits" xlink:title="UnrecognizedTaxBenefits" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="UnrecognizedTaxBenefits" xlink:title="definition: OperatingLossCarryforwardsLineItems to UnrecognizedTaxBenefits" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions" xlink:label="UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions" xlink:title="UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions" xlink:title="definition: OperatingLossCarryforwardsLineItems to UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions" xlink:label="UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions" xlink:title="UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions" xlink:title="definition: OperatingLossCarryforwardsLineItems to UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions" xlink:label="UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions" xlink:title="UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions" xlink:title="definition: OperatingLossCarryforwardsLineItems to UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities" xlink:label="UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities" xlink:title="UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities" xlink:title="definition: OperatingLossCarryforwardsLineItems to UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations" xlink:label="UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations" xlink:title="UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations" xlink:title="definition: OperatingLossCarryforwardsLineItems to UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OperatingLossCarryforwardsTable" xlink:label="OperatingLossCarryforwardsTable" xlink:title="OperatingLossCarryforwardsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="OperatingLossCarryforwardsTable" xlink:title="definition: OperatingLossCarryforwardsLineItems to OperatingLossCarryforwardsTable" order="23.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxAuthorityAxis" xlink:label="IncomeTaxAuthorityAxis" xlink:title="IncomeTaxAuthorityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="OperatingLossCarryforwardsTable" xlink:to="IncomeTaxAuthorityAxis" xlink:title="definition: OperatingLossCarryforwardsTable to IncomeTaxAuthorityAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:label="IncomeTaxAuthorityDomain" xlink:title="IncomeTaxAuthorityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="IncomeTaxAuthorityAxis" xlink:to="IncomeTaxAuthorityDomain" xlink:title="definition: IncomeTaxAuthorityAxis to IncomeTaxAuthorityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:label="IncomeTaxAuthorityDomain_2" xlink:title="IncomeTaxAuthorityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="IncomeTaxAuthorityAxis" xlink:to="IncomeTaxAuthorityDomain_2" xlink:title="definition: IncomeTaxAuthorityAxis to IncomeTaxAuthorityDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DomesticCountryMember" xlink:label="DomesticCountryMember" xlink:title="DomesticCountryMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxAuthorityDomain" xlink:to="DomesticCountryMember" xlink:title="definition: IncomeTaxAuthorityDomain to DomesticCountryMember" order="1.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxAuthorityDomain" xlink:to="ForeignCountryMember" xlink:title="definition: IncomeTaxAuthorityDomain to ForeignCountryMember" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxAuthorityDomain" xlink:to="StateAndLocalJurisdictionMember" xlink:title="definition: IncomeTaxAuthorityDomain to StateAndLocalJurisdictionMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_ForeignJurisdictionsMember" xlink:label="ForeignJurisdictionsMember" xlink:title="ForeignJurisdictionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxAuthorityDomain" xlink:to="ForeignJurisdictionsMember" xlink:title="definition: IncomeTaxAuthorityDomain to ForeignJurisdictionsMember" order="4.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="OperatingLossCarryforwardsTable" xlink:to="RangeAxis" xlink:title="definition: OperatingLossCarryforwardsTable to RangeAxis" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/IncomeTaxesDetailsCalc01" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/EarningsPerShareDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SubsequentEventLineItems" xlink:label="SubsequentEventLineItems" xlink:title="SubsequentEventLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationGross" xlink:label="StockIssuedDuringPeriodSharesShareBasedCompensationGross" xlink:title="StockIssuedDuringPeriodSharesShareBasedCompensationGross" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsequentEventLineItems" xlink:to="StockIssuedDuringPeriodSharesShareBasedCompensationGross" xlink:title="definition: SubsequentEventLineItems to StockIssuedDuringPeriodSharesShareBasedCompensationGross" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SubsequentEventTable" xlink:label="SubsequentEventTable" xlink:title="SubsequentEventTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="SubsequentEventLineItems" xlink:to="SubsequentEventTable" xlink:title="definition: SubsequentEventLineItems to SubsequentEventTable" order="2.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="SubsequentEventTypeAxis" xlink:title="SubsequentEventTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="SubsequentEventTable" xlink:to="SubsequentEventTypeAxis" xlink:title="definition: SubsequentEventTable to SubsequentEventTypeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="SubsequentEventTypeDomain" xlink:title="SubsequentEventTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="SubsequentEventTypeAxis" xlink:to="SubsequentEventTypeDomain" xlink:title="definition: SubsequentEventTypeAxis to SubsequentEventTypeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="SubsequentEventTypeDomain_2" xlink:title="SubsequentEventTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SubsequentEventTypeAxis" xlink:to="SubsequentEventTypeDomain_2" xlink:title="definition: SubsequentEventTypeAxis to SubsequentEventTypeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="SubsequentEventMember" xlink:title="SubsequentEventMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsequentEventTypeDomain" xlink:to="SubsequentEventMember" xlink:title="definition: SubsequentEventTypeDomain to SubsequentEventMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:label="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:title="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:label="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:title="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:to="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:title="definition: AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems to AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:label="ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:title="ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:to="ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:title="definition: AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems to ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" order="2.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:label="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:title="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:to="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:title="definition: ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable to AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="AntidilutiveSecuritiesNameDomain" xlink:title="AntidilutiveSecuritiesNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="AntidilutiveSecuritiesNameDomain" xlink:title="definition: AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis to AntidilutiveSecuritiesNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="AntidilutiveSecuritiesNameDomain_2" xlink:title="AntidilutiveSecuritiesNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="AntidilutiveSecuritiesNameDomain_2" xlink:title="definition: AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis to AntidilutiveSecuritiesNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StockCompensationPlanMember" xlink:label="StockCompensationPlanMember" xlink:title="StockCompensationPlanMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AntidilutiveSecuritiesNameDomain" xlink:to="StockCompensationPlanMember" xlink:title="definition: AntidilutiveSecuritiesNameDomain to StockCompensationPlanMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConvertibleDebtSecuritiesMember" xlink:label="ConvertibleDebtSecuritiesMember" xlink:title="ConvertibleDebtSecuritiesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AntidilutiveSecuritiesNameDomain" xlink:to="ConvertibleDebtSecuritiesMember" xlink:title="definition: AntidilutiveSecuritiesNameDomain to ConvertibleDebtSecuritiesMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/SubsidiaryShareRepurchaseDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:label="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:title="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MinorityInterestOwnershipPercentageByParent" xlink:label="MinorityInterestOwnershipPercentageByParent" xlink:title="MinorityInterestOwnershipPercentageByParent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="MinorityInterestOwnershipPercentageByParent" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to MinorityInterestOwnershipPercentageByParent" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PaymentsToMinorityShareholders" xlink:label="PaymentsToMinorityShareholders" xlink:title="PaymentsToMinorityShareholders" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="PaymentsToMinorityShareholders" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to PaymentsToMinorityShareholders" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangeDueToNetIncomeAttributableToParentAndEffectsOfChangesNetAbstract" xlink:label="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangeDueToNetIncomeAttributableToParentAndEffectsOfChangesNetAbstract" xlink:title="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangeDueToNetIncomeAttributableToParentAndEffectsOfChangesNetAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangeDueToNetIncomeAttributableToParentAndEffectsOfChangesNetAbstract" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangeDueToNetIncomeAttributableToParentAndEffectsOfChangesNetAbstract" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="NetIncomeLoss" xlink:title="NetIncomeLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="NetIncomeLoss" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to NetIncomeLoss" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangesRepurchaseOfSharesBySubsidiary" xlink:label="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangesRepurchaseOfSharesBySubsidiary" xlink:title="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangesRepurchaseOfSharesBySubsidiary" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangesRepurchaseOfSharesBySubsidiary" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangesRepurchaseOfSharesBySubsidiary" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangeDueToNetIncomeAttributableToParentAndEffectsOfChangesNet" xlink:label="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangeDueToNetIncomeAttributableToParentAndEffectsOfChangesNet" xlink:title="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangeDueToNetIncomeAttributableToParentAndEffectsOfChangesNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangeDueToNetIncomeAttributableToParentAndEffectsOfChangesNet" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangeDueToNetIncomeAttributableToParentAndEffectsOfChangesNet" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable" xlink:label="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable" xlink:title="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems" xlink:to="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems to ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable" order="7.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="LegalEntityAxis" xlink:title="LegalEntityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable" xlink:to="LegalEntityAxis" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable to LegalEntityAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain" xlink:title="EntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LegalEntityAxis" xlink:to="EntityDomain" xlink:title="definition: LegalEntityAxis to EntityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain_2" xlink:title="EntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LegalEntityAxis" xlink:to="EntityDomain_2" xlink:title="definition: LegalEntityAxis to EntityDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_PsmcStockRepurchaseProgramMember" xlink:label="PsmcStockRepurchaseProgramMember" xlink:title="PsmcStockRepurchaseProgramMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="PsmcStockRepurchaseProgramMember" xlink:title="definition: EntityDomain to PsmcStockRepurchaseProgramMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="StatementEquityComponentsAxis" xlink:title="StatementEquityComponentsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable" xlink:to="StatementEquityComponentsAxis" xlink:title="definition: ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetTable to StatementEquityComponentsAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain_2" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain_2" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="AdditionalPaidInCapitalMember" xlink:title="AdditionalPaidInCapitalMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="AdditionalPaidInCapitalMember" xlink:title="definition: EquityComponentDomain to AdditionalPaidInCapitalMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="AccumulatedOtherComprehensiveIncomeMember" xlink:title="AccumulatedOtherComprehensiveIncomeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="AccumulatedOtherComprehensiveIncomeMember" xlink:title="definition: EquityComponentDomain to AccumulatedOtherComprehensiveIncomeMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/CommitmentsAndContingenciesDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/GeographicAndSignificantCustomerInformationDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskLineItems" xlink:label="ConcentrationRiskLineItems" xlink:title="ConcentrationRiskLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:label="ConcentrationRiskPercentage1" xlink:title="ConcentrationRiskPercentage1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConcentrationRiskLineItems" xlink:to="ConcentrationRiskPercentage1" xlink:title="definition: ConcentrationRiskLineItems to ConcentrationRiskPercentage1" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskTable" xlink:label="ConcentrationRiskTable" xlink:title="ConcentrationRiskTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ConcentrationRiskLineItems" xlink:to="ConcentrationRiskTable" xlink:title="definition: ConcentrationRiskLineItems to ConcentrationRiskTable" order="2.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:label="ConcentrationRiskByBenchmarkAxis" xlink:title="ConcentrationRiskByBenchmarkAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ConcentrationRiskTable" xlink:to="ConcentrationRiskByBenchmarkAxis" xlink:title="definition: ConcentrationRiskTable to ConcentrationRiskByBenchmarkAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="ConcentrationRiskBenchmarkDomain" xlink:title="ConcentrationRiskBenchmarkDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ConcentrationRiskByBenchmarkAxis" xlink:to="ConcentrationRiskBenchmarkDomain" xlink:title="definition: ConcentrationRiskByBenchmarkAxis to ConcentrationRiskBenchmarkDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="ConcentrationRiskBenchmarkDomain_2" xlink:title="ConcentrationRiskBenchmarkDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ConcentrationRiskByBenchmarkAxis" xlink:to="ConcentrationRiskBenchmarkDomain_2" xlink:title="definition: ConcentrationRiskByBenchmarkAxis to ConcentrationRiskBenchmarkDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SalesRevenueNetMember" xlink:label="SalesRevenueNetMember" xlink:title="SalesRevenueNetMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConcentrationRiskBenchmarkDomain" xlink:to="SalesRevenueNetMember" xlink:title="definition: ConcentrationRiskBenchmarkDomain to SalesRevenueNetMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="ConcentrationRiskByTypeAxis" xlink:title="ConcentrationRiskByTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ConcentrationRiskTable" xlink:to="ConcentrationRiskByTypeAxis" xlink:title="definition: ConcentrationRiskTable to ConcentrationRiskByTypeAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="ConcentrationRiskTypeDomain" xlink:title="ConcentrationRiskTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ConcentrationRiskByTypeAxis" xlink:to="ConcentrationRiskTypeDomain" xlink:title="definition: ConcentrationRiskByTypeAxis to ConcentrationRiskTypeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="ConcentrationRiskTypeDomain_2" xlink:title="ConcentrationRiskTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ConcentrationRiskByTypeAxis" xlink:to="ConcentrationRiskTypeDomain_2" xlink:title="definition: ConcentrationRiskByTypeAxis to ConcentrationRiskTypeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CustomerConcentrationRiskMember" xlink:label="CustomerConcentrationRiskMember" xlink:title="CustomerConcentrationRiskMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConcentrationRiskTypeDomain" xlink:to="CustomerConcentrationRiskMember" xlink:title="definition: ConcentrationRiskTypeDomain to CustomerConcentrationRiskMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MajorCustomersAxis" xlink:label="MajorCustomersAxis" xlink:title="MajorCustomersAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ConcentrationRiskTable" xlink:to="MajorCustomersAxis" xlink:title="definition: ConcentrationRiskTable to MajorCustomersAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="NameOfMajorCustomerDomain" xlink:title="NameOfMajorCustomerDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="MajorCustomersAxis" xlink:to="NameOfMajorCustomerDomain" xlink:title="definition: MajorCustomersAxis to NameOfMajorCustomerDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="NameOfMajorCustomerDomain_2" xlink:title="NameOfMajorCustomerDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="MajorCustomersAxis" xlink:to="NameOfMajorCustomerDomain_2" xlink:title="definition: MajorCustomersAxis to NameOfMajorCustomerDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_MajorCustomer1Member" xlink:label="MajorCustomer1Member" xlink:title="MajorCustomer1Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NameOfMajorCustomerDomain" xlink:to="MajorCustomer1Member" xlink:title="definition: NameOfMajorCustomerDomain to MajorCustomer1Member" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_OtherCustomerMember" xlink:label="OtherCustomerMember" xlink:title="OtherCustomerMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NameOfMajorCustomerDomain" xlink:to="OtherCustomerMember" xlink:title="definition: NameOfMajorCustomerDomain to OtherCustomerMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:label="RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:title="RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SalesRevenueGoodsNet" xlink:label="SalesRevenueGoodsNet" xlink:title="SalesRevenueGoodsNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:to="SalesRevenueGoodsNet" xlink:title="definition: RevenuesFromExternalCustomersAndLongLivedAssetsLineItems to SalesRevenueGoodsNet" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="PropertyPlantAndEquipmentNet" xlink:title="PropertyPlantAndEquipmentNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:to="PropertyPlantAndEquipmentNet" xlink:title="definition: RevenuesFromExternalCustomersAndLongLivedAssetsLineItems to PropertyPlantAndEquipmentNet" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:label="ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:title="ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:to="ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:title="definition: RevenuesFromExternalCustomersAndLongLivedAssetsLineItems to ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementGeographicalAxis" xlink:label="StatementGeographicalAxis" xlink:title="StatementGeographicalAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:to="StatementGeographicalAxis" xlink:title="definition: ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable to StatementGeographicalAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="SegmentGeographicalDomain" xlink:title="SegmentGeographicalDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementGeographicalAxis" xlink:to="SegmentGeographicalDomain" xlink:title="definition: StatementGeographicalAxis to SegmentGeographicalDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="SegmentGeographicalDomain_2" xlink:title="SegmentGeographicalDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementGeographicalAxis" xlink:to="SegmentGeographicalDomain_2" xlink:title="definition: StatementGeographicalAxis to SegmentGeographicalDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/country/2016/country-2016-01-31.xsd#country_TW" xlink:label="TW" xlink:title="TW" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="TW" xlink:title="definition: SegmentGeographicalDomain to TW" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/country/2016/country-2016-01-31.xsd#country_KR" xlink:label="KR" xlink:title="KR" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="KR" xlink:title="definition: SegmentGeographicalDomain to KR" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/country/2016/country-2016-01-31.xsd#country_US" xlink:label="US" xlink:title="US" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="US" xlink:title="definition: SegmentGeographicalDomain to US" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EuropeMember" xlink:label="EuropeMember" xlink:title="EuropeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="EuropeMember" xlink:title="definition: SegmentGeographicalDomain to EuropeMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_AllOtherAsiaMember" xlink:label="AllOtherAsiaMember" xlink:title="AllOtherAsiaMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="AllOtherAsiaMember" xlink:title="definition: SegmentGeographicalDomain to AllOtherAsiaMember" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProductOrServiceAxis" xlink:label="ProductOrServiceAxis" xlink:title="ProductOrServiceAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:to="ProductOrServiceAxis" xlink:title="definition: ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable to ProductOrServiceAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProductsAndServicesDomain" xlink:label="ProductsAndServicesDomain" xlink:title="ProductsAndServicesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ProductOrServiceAxis" xlink:to="ProductsAndServicesDomain" xlink:title="definition: ProductOrServiceAxis to ProductsAndServicesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProductsAndServicesDomain" xlink:label="ProductsAndServicesDomain_2" xlink:title="ProductsAndServicesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ProductOrServiceAxis" xlink:to="ProductsAndServicesDomain_2" xlink:title="definition: ProductOrServiceAxis to ProductsAndServicesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_IntegratedCircuitsMember" xlink:label="IntegratedCircuitsMember" xlink:title="IntegratedCircuitsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="IntegratedCircuitsMember" xlink:title="definition: ProductsAndServicesDomain to IntegratedCircuitsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_FlatPanelDisplaysMember" xlink:label="FlatPanelDisplaysMember" xlink:title="FlatPanelDisplaysMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="FlatPanelDisplaysMember" xlink:title="definition: ProductsAndServicesDomain to FlatPanelDisplaysMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/ChangesInAccumulatedOtherComprehensiveIncomeByComponentDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:label="AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:title="AccumulatedOtherComprehensiveIncomeLossLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="StockholdersEquity" xlink:title="StockholdersEquity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:to="StockholdersEquity" xlink:title="definition: AccumulatedOtherComprehensiveIncomeLossLineItems to StockholdersEquity" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax" xlink:label="OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax" xlink:title="OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:to="OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax" xlink:title="definition: AccumulatedOtherComprehensiveIncomeLossLineItems to OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax" xlink:label="ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax" xlink:title="ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:to="ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax" xlink:title="definition: AccumulatedOtherComprehensiveIncomeLossLineItems to ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:label="OtherComprehensiveIncomeLossNetOfTax" xlink:title="OtherComprehensiveIncomeLossNetOfTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:to="OtherComprehensiveIncomeLossNetOfTax" xlink:title="definition: AccumulatedOtherComprehensiveIncomeLossLineItems to OtherComprehensiveIncomeLossNetOfTax" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest" xlink:label="OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest" xlink:title="OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:to="OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest" xlink:title="definition: AccumulatedOtherComprehensiveIncomeLossLineItems to OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable" xlink:label="AccumulatedOtherComprehensiveIncomeLossTable" xlink:title="AccumulatedOtherComprehensiveIncomeLossTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:to="AccumulatedOtherComprehensiveIncomeLossTable" xlink:title="definition: AccumulatedOtherComprehensiveIncomeLossLineItems to AccumulatedOtherComprehensiveIncomeLossTable" order="6.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="StatementEquityComponentsAxis" xlink:title="StatementEquityComponentsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="AccumulatedOtherComprehensiveIncomeLossTable" xlink:to="StatementEquityComponentsAxis" xlink:title="definition: AccumulatedOtherComprehensiveIncomeLossTable to StatementEquityComponentsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain_2" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain_2" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="AccumulatedOtherComprehensiveIncomeMember" xlink:title="AccumulatedOtherComprehensiveIncomeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="AccumulatedOtherComprehensiveIncomeMember" xlink:title="definition: EquityComponentDomain to AccumulatedOtherComprehensiveIncomeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AociIncludingPortionAttributableToNoncontrollingInterestMember" xlink:label="AociIncludingPortionAttributableToNoncontrollingInterestMember" xlink:title="AociIncludingPortionAttributableToNoncontrollingInterestMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="AociIncludingPortionAttributableToNoncontrollingInterestMember" xlink:title="definition: EquityComponentDomain to AociIncludingPortionAttributableToNoncontrollingInterestMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AociAttributableToNoncontrollingInterestMember" xlink:label="AociAttributableToNoncontrollingInterestMember" xlink:title="AociAttributableToNoncontrollingInterestMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="AociAttributableToNoncontrollingInterestMember" xlink:title="definition: EquityComponentDomain to AociAttributableToNoncontrollingInterestMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccumulatedForeignCurrencyAdjustmentAttributableToNoncontrollingInterestMember" xlink:label="AccumulatedForeignCurrencyAdjustmentAttributableToNoncontrollingInterestMember" xlink:title="AccumulatedForeignCurrencyAdjustmentAttributableToNoncontrollingInterestMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AociAttributableToNoncontrollingInterestMember" xlink:to="AccumulatedForeignCurrencyAdjustmentAttributableToNoncontrollingInterestMember" xlink:title="definition: AociAttributableToNoncontrollingInterestMember to AccumulatedForeignCurrencyAdjustmentAttributableToNoncontrollingInterestMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccumulatedNetGainLossFromCashFlowHedgesAttributableToNoncontrollingInterestMember" xlink:label="AccumulatedNetGainLossFromCashFlowHedgesAttributableToNoncontrollingInterestMember" xlink:title="AccumulatedNetGainLossFromCashFlowHedgesAttributableToNoncontrollingInterestMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AociAttributableToNoncontrollingInterestMember" xlink:to="AccumulatedNetGainLossFromCashFlowHedgesAttributableToNoncontrollingInterestMember" xlink:title="definition: AociAttributableToNoncontrollingInterestMember to AccumulatedNetGainLossFromCashFlowHedgesAttributableToNoncontrollingInterestMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_AccumulatedOtherComprehensiveIncomeAttributableToNoncontrollingInterestOtherMember" xlink:label="AccumulatedOtherComprehensiveIncomeAttributableToNoncontrollingInterestOtherMember" xlink:title="AccumulatedOtherComprehensiveIncomeAttributableToNoncontrollingInterestOtherMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AociAttributableToNoncontrollingInterestMember" xlink:to="AccumulatedOtherComprehensiveIncomeAttributableToNoncontrollingInterestOtherMember" xlink:title="definition: AociAttributableToNoncontrollingInterestMember to AccumulatedOtherComprehensiveIncomeAttributableToNoncontrollingInterestOtherMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccumulatedForeignCurrencyAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember" xlink:label="AccumulatedForeignCurrencyAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember" xlink:title="AccumulatedForeignCurrencyAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AociIncludingPortionAttributableToNoncontrollingInterestMember" xlink:to="AccumulatedForeignCurrencyAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember" xlink:title="definition: AociIncludingPortionAttributableToNoncontrollingInterestMember to AccumulatedForeignCurrencyAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccumulatedNetGainLossFromCashFlowHedgesIncludingPortionAttributableToNoncontrollingInterestMember" xlink:label="AccumulatedNetGainLossFromCashFlowHedgesIncludingPortionAttributableToNoncontrollingInterestMember" xlink:title="AccumulatedNetGainLossFromCashFlowHedgesIncludingPortionAttributableToNoncontrollingInterestMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AociIncludingPortionAttributableToNoncontrollingInterestMember" xlink:to="AccumulatedNetGainLossFromCashFlowHedgesIncludingPortionAttributableToNoncontrollingInterestMember" xlink:title="definition: AociIncludingPortionAttributableToNoncontrollingInterestMember to AccumulatedNetGainLossFromCashFlowHedgesIncludingPortionAttributableToNoncontrollingInterestMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_AccumulatedOtherComprehensiveIncomeIncludingPortionAttributableToNoncontrollingInterestOtherMember" xlink:label="AccumulatedOtherComprehensiveIncomeIncludingPortionAttributableToNoncontrollingInterestOtherMember" xlink:title="AccumulatedOtherComprehensiveIncomeIncludingPortionAttributableToNoncontrollingInterestOtherMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AociIncludingPortionAttributableToNoncontrollingInterestMember" xlink:to="AccumulatedOtherComprehensiveIncomeIncludingPortionAttributableToNoncontrollingInterestOtherMember" xlink:title="definition: AociIncludingPortionAttributableToNoncontrollingInterestMember to AccumulatedOtherComprehensiveIncomeIncludingPortionAttributableToNoncontrollingInterestOtherMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccumulatedTranslationAdjustmentMember" xlink:label="AccumulatedTranslationAdjustmentMember" xlink:title="AccumulatedTranslationAdjustmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AccumulatedOtherComprehensiveIncomeMember" xlink:to="AccumulatedTranslationAdjustmentMember" xlink:title="definition: AccumulatedOtherComprehensiveIncomeMember to AccumulatedTranslationAdjustmentMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember" xlink:label="AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember" xlink:title="AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AccumulatedOtherComprehensiveIncomeMember" xlink:to="AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember" xlink:title="definition: AccumulatedOtherComprehensiveIncomeMember to AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_AccumulatedOtherComprehensiveIncomeOtherMember" xlink:label="AccumulatedOtherComprehensiveIncomeOtherMember" xlink:title="AccumulatedOtherComprehensiveIncomeOtherMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AccumulatedOtherComprehensiveIncomeMember" xlink:to="AccumulatedOtherComprehensiveIncomeOtherMember" xlink:title="definition: AccumulatedOtherComprehensiveIncomeMember to AccumulatedOtherComprehensiveIncomeOtherMember" order="3.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/OtherRelatedPartyTransactionsDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="RelatedPartyTransactionLineItems" xlink:title="RelatedPartyTransactionLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionAmountsOfTransaction" xlink:label="RelatedPartyTransactionAmountsOfTransaction" xlink:title="RelatedPartyTransactionAmountsOfTransaction" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="RelatedPartyTransactionAmountsOfTransaction" xlink:title="definition: RelatedPartyTransactionLineItems to RelatedPartyTransactionAmountsOfTransaction" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccountsPayableRelatedPartiesCurrent" xlink:label="AccountsPayableRelatedPartiesCurrent" xlink:title="AccountsPayableRelatedPartiesCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="AccountsPayableRelatedPartiesCurrent" xlink:title="definition: RelatedPartyTransactionLineItems to AccountsPayableRelatedPartiesCurrent" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:title="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="RelatedPartyTransactionLineItems" xlink:to="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:title="definition: RelatedPartyTransactionLineItems to ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="RelatedPartyTransactionsByRelatedPartyAxis" xlink:title="RelatedPartyTransactionsByRelatedPartyAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="RelatedPartyTransactionsByRelatedPartyAxis" xlink:title="definition: ScheduleOfRelatedPartyTransactionsByRelatedPartyTable to RelatedPartyTransactionsByRelatedPartyAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="RelatedPartyDomain" xlink:title="RelatedPartyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="RelatedPartyDomain" xlink:title="definition: RelatedPartyTransactionsByRelatedPartyAxis to RelatedPartyDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="RelatedPartyDomain_2" xlink:title="RelatedPartyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="RelatedPartyDomain_2" xlink:title="definition: RelatedPartyTransactionsByRelatedPartyAxis to RelatedPartyDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_InformationTechnologyServicesProviderMember" xlink:label="InformationTechnologyServicesProviderMember" xlink:title="InformationTechnologyServicesProviderMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyDomain" xlink:to="InformationTechnologyServicesProviderMember" xlink:title="definition: RelatedPartyDomain to InformationTechnologyServicesProviderMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_InformationTechnologyServicesProvider1Member" xlink:label="InformationTechnologyServicesProvider1Member" xlink:title="InformationTechnologyServicesProvider1Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyDomain" xlink:to="InformationTechnologyServicesProvider1Member" xlink:title="definition: RelatedPartyDomain to InformationTechnologyServicesProvider1Member" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_PhotomaskBlankSupplierMember" xlink:label="PhotomaskBlankSupplierMember" xlink:title="PhotomaskBlankSupplierMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyDomain" xlink:to="PhotomaskBlankSupplierMember" xlink:title="definition: RelatedPartyDomain to PhotomaskBlankSupplierMember" order="3.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/FairValueMeasurementsDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:label="FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:title="FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract" xlink:label="FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract" xlink:title="FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:to="FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract" xlink:title="definition: FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems to FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConvertibleDebtFairValueDisclosures" xlink:label="ConvertibleDebtFairValueDisclosures" xlink:title="ConvertibleDebtFairValueDisclosures" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:to="ConvertibleDebtFairValueDisclosures" xlink:title="definition: FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems to ConvertibleDebtFairValueDisclosures" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable" xlink:label="FairValueByBalanceSheetGroupingTable" xlink:title="FairValueByBalanceSheetGroupingTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:to="FairValueByBalanceSheetGroupingTable" xlink:title="definition: FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems to FairValueByBalanceSheetGroupingTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueByMeasurementBasisAxis" xlink:label="FairValueByMeasurementBasisAxis" xlink:title="FairValueByMeasurementBasisAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueByBalanceSheetGroupingTable" xlink:to="FairValueByMeasurementBasisAxis" xlink:title="definition: FairValueByBalanceSheetGroupingTable to FairValueByMeasurementBasisAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain" xlink:label="FairValueDisclosureItemAmountsDomain" xlink:title="FairValueDisclosureItemAmountsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="FairValueByMeasurementBasisAxis" xlink:to="FairValueDisclosureItemAmountsDomain" xlink:title="definition: FairValueByMeasurementBasisAxis to FairValueDisclosureItemAmountsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:label="PortionAtFairValueFairValueDisclosureMember" xlink:title="PortionAtFairValueFairValueDisclosureMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueDisclosureItemAmountsDomain" xlink:to="PortionAtFairValueFairValueDisclosureMember" xlink:title="definition: FairValueDisclosureItemAmountsDomain to PortionAtFairValueFairValueDisclosureMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:label="PortionAtFairValueFairValueDisclosureMember_2" xlink:title="PortionAtFairValueFairValueDisclosureMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="FairValueByMeasurementBasisAxis" xlink:to="PortionAtFairValueFairValueDisclosureMember_2" xlink:title="definition: FairValueByMeasurementBasisAxis to PortionAtFairValueFairValueDisclosureMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember" xlink:label="EstimateOfFairValueFairValueDisclosureMember" xlink:title="EstimateOfFairValueFairValueDisclosureMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueDisclosureItemAmountsDomain" xlink:to="EstimateOfFairValueFairValueDisclosureMember" xlink:title="definition: FairValueDisclosureItemAmountsDomain to EstimateOfFairValueFairValueDisclosureMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:label="CarryingReportedAmountFairValueDisclosureMember" xlink:title="CarryingReportedAmountFairValueDisclosureMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueDisclosureItemAmountsDomain" xlink:to="CarryingReportedAmountFairValueDisclosureMember" xlink:title="definition: FairValueDisclosureItemAmountsDomain to CarryingReportedAmountFairValueDisclosureMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="LongtermDebtTypeAxis" xlink:title="LongtermDebtTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueByBalanceSheetGroupingTable" xlink:to="LongtermDebtTypeAxis" xlink:title="definition: FairValueByBalanceSheetGroupingTable to LongtermDebtTypeAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="LongtermDebtTypeDomain" xlink:title="LongtermDebtTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LongtermDebtTypeAxis" xlink:to="LongtermDebtTypeDomain" xlink:title="definition: LongtermDebtTypeAxis to LongtermDebtTypeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="LongtermDebtTypeDomain_2" xlink:title="LongtermDebtTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LongtermDebtTypeAxis" xlink:to="LongtermDebtTypeDomain_2" xlink:title="definition: LongtermDebtTypeAxis to LongtermDebtTypeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_ConvertibleSeniorNotesDueOnApril2019Member" xlink:label="ConvertibleSeniorNotesDueOnApril2019Member" xlink:title="ConvertibleSeniorNotesDueOnApril2019Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongtermDebtTypeDomain" xlink:to="ConvertibleSeniorNotesDueOnApril2019Member" xlink:title="definition: LongtermDebtTypeDomain to ConvertibleSeniorNotesDueOnApril2019Member" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_ConvertibleSeniorNotesDueOnApril2016Member" xlink:label="ConvertibleSeniorNotesDueOnApril2016Member" xlink:title="ConvertibleSeniorNotesDueOnApril2016Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongtermDebtTypeDomain" xlink:to="ConvertibleSeniorNotesDueOnApril2016Member" xlink:title="definition: LongtermDebtTypeDomain to ConvertibleSeniorNotesDueOnApril2016Member" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:title="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AssetsFairValueDisclosure" xlink:label="AssetsFairValueDisclosure" xlink:title="AssetsFairValueDisclosure" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="AssetsFairValueDisclosure" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to AssetsFairValueDisclosure" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosure" xlink:label="LiabilitiesFairValueDisclosure" xlink:title="LiabilitiesFairValueDisclosure" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="LiabilitiesFairValueDisclosure" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to LiabilitiesFairValueDisclosure" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:title="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="FairValueByMeasurementFrequencyAxis" xlink:title="FairValueByMeasurementFrequencyAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:to="FairValueByMeasurementFrequencyAxis" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable to FairValueByMeasurementFrequencyAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="FairValueMeasurementFrequencyDomain" xlink:title="FairValueMeasurementFrequencyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="FairValueByMeasurementFrequencyAxis" xlink:to="FairValueMeasurementFrequencyDomain" xlink:title="definition: FairValueByMeasurementFrequencyAxis to FairValueMeasurementFrequencyDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="FairValueMeasurementFrequencyDomain_2" xlink:title="FairValueMeasurementFrequencyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="FairValueByMeasurementFrequencyAxis" xlink:to="FairValueMeasurementFrequencyDomain_2" xlink:title="definition: FairValueByMeasurementFrequencyAxis to FairValueMeasurementFrequencyDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="FairValueMeasurementsRecurringMember" xlink:title="FairValueMeasurementsRecurringMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueMeasurementFrequencyDomain" xlink:to="FairValueMeasurementsRecurringMember" xlink:title="definition: FairValueMeasurementFrequencyDomain to FairValueMeasurementsRecurringMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueMeasurementsNonrecurringMember" xlink:label="FairValueMeasurementsNonrecurringMember" xlink:title="FairValueMeasurementsNonrecurringMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueMeasurementFrequencyDomain" xlink:to="FairValueMeasurementsNonrecurringMember" xlink:title="definition: FairValueMeasurementFrequencyDomain to FairValueMeasurementsNonrecurringMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/GainsOnSaleOfInvestmentsDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfInvestmentsLineItems" xlink:label="ScheduleOfInvestmentsLineItems" xlink:title="ScheduleOfInvestmentsLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_GainOnSaleOfInvestments" xlink:label="GainOnSaleOfInvestments" xlink:title="GainOnSaleOfInvestments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfInvestmentsLineItems" xlink:to="GainOnSaleOfInvestments" xlink:title="definition: ScheduleOfInvestmentsLineItems to GainOnSaleOfInvestments" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfInvestmentsTable" xlink:label="ScheduleOfInvestmentsTable" xlink:title="ScheduleOfInvestmentsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ScheduleOfInvestmentsLineItems" xlink:to="ScheduleOfInvestmentsTable" xlink:title="definition: ScheduleOfInvestmentsLineItems to ScheduleOfInvestmentsTable" order="2.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/invest/2013/invest-2013-01-31.xsd#invest_InvestmentAxis" xlink:label="InvestmentAxis" xlink:title="InvestmentAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfInvestmentsTable" xlink:to="InvestmentAxis" xlink:title="definition: ScheduleOfInvestmentsTable to InvestmentAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/invest/2013/invest-2013-01-31.xsd#invest_InvestmentDomain" xlink:label="InvestmentDomain" xlink:title="InvestmentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="InvestmentAxis" xlink:to="InvestmentDomain" xlink:title="definition: InvestmentAxis to InvestmentDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/invest/2013/invest-2013-01-31.xsd#invest_InvestmentDomain" xlink:label="InvestmentDomain_2" xlink:title="InvestmentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="InvestmentAxis" xlink:to="InvestmentDomain_2" xlink:title="definition: InvestmentAxis to InvestmentDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_InvestmentInForeignEntityMember" xlink:label="InvestmentInForeignEntityMember" xlink:title="InvestmentInForeignEntityMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="InvestmentDomain" xlink:to="InvestmentInForeignEntityMember" xlink:title="definition: InvestmentDomain to InvestmentInForeignEntityMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/ExpansionIntoChinaDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/QuarterlyResultsOfOperationsUnauditedDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="DebtInstrumentLineItems" xlink:title="DebtInstrumentLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtRelatedCommitmentFeesAndDebtIssuanceCosts" xlink:label="DebtRelatedCommitmentFeesAndDebtIssuanceCosts" xlink:title="DebtRelatedCommitmentFeesAndDebtIssuanceCosts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtRelatedCommitmentFeesAndDebtIssuanceCosts" xlink:title="definition: DebtInstrumentLineItems to DebtRelatedCommitmentFeesAndDebtIssuanceCosts" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConvertibleDebtFairValueDisclosures" xlink:label="ConvertibleDebtFairValueDisclosures" xlink:title="ConvertibleDebtFairValueDisclosures" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="ConvertibleDebtFairValueDisclosures" xlink:title="definition: DebtInstrumentLineItems to ConvertibleDebtFairValueDisclosures" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="DebtInstrumentInterestRateStatedPercentage" xlink:title="DebtInstrumentInterestRateStatedPercentage" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentInterestRateStatedPercentage" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentInterestRateStatedPercentage" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="DebtInstrumentTable" xlink:title="DebtInstrumentTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentTable" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentTable" order="4.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="LongtermDebtTypeAxis" xlink:title="LongtermDebtTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DebtInstrumentTable" xlink:to="LongtermDebtTypeAxis" xlink:title="definition: DebtInstrumentTable to LongtermDebtTypeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="LongtermDebtTypeDomain" xlink:title="LongtermDebtTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LongtermDebtTypeAxis" xlink:to="LongtermDebtTypeDomain" xlink:title="definition: LongtermDebtTypeAxis to LongtermDebtTypeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="LongtermDebtTypeDomain_2" xlink:title="LongtermDebtTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LongtermDebtTypeAxis" xlink:to="LongtermDebtTypeDomain_2" xlink:title="definition: LongtermDebtTypeAxis to LongtermDebtTypeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_ConvertibleSeniorNotesMember" xlink:label="ConvertibleSeniorNotesMember" xlink:title="ConvertibleSeniorNotesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongtermDebtTypeDomain" xlink:to="ConvertibleSeniorNotesMember" xlink:title="definition: LongtermDebtTypeDomain to ConvertibleSeniorNotesMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfInvestmentsLineItems" xlink:label="ScheduleOfInvestmentsLineItems" xlink:title="ScheduleOfInvestmentsLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_GainOnSaleOfInvestments" xlink:label="GainOnSaleOfInvestments" xlink:title="GainOnSaleOfInvestments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfInvestmentsLineItems" xlink:to="GainOnSaleOfInvestments" xlink:title="definition: ScheduleOfInvestmentsLineItems to GainOnSaleOfInvestments" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:label="ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:title="ValuationAllowanceDeferredTaxAssetChangeInAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfInvestmentsLineItems" xlink:to="ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:title="definition: ScheduleOfInvestmentsLineItems to ValuationAllowanceDeferredTaxAssetChangeInAmount" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfInvestmentsTable" xlink:label="ScheduleOfInvestmentsTable" xlink:title="ScheduleOfInvestmentsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ScheduleOfInvestmentsLineItems" xlink:to="ScheduleOfInvestmentsTable" xlink:title="definition: ScheduleOfInvestmentsLineItems to ScheduleOfInvestmentsTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/invest/2013/invest-2013-01-31.xsd#invest_InvestmentAxis" xlink:label="InvestmentAxis" xlink:title="InvestmentAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfInvestmentsTable" xlink:to="InvestmentAxis" xlink:title="definition: ScheduleOfInvestmentsTable to InvestmentAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/invest/2013/invest-2013-01-31.xsd#invest_InvestmentDomain" xlink:label="InvestmentDomain" xlink:title="InvestmentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="InvestmentAxis" xlink:to="InvestmentDomain" xlink:title="definition: InvestmentAxis to InvestmentDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/invest/2013/invest-2013-01-31.xsd#invest_InvestmentDomain" xlink:label="InvestmentDomain_2" xlink:title="InvestmentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="InvestmentAxis" xlink:to="InvestmentDomain_2" xlink:title="definition: InvestmentAxis to InvestmentDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="plab-20161030.xsd#plab_InvestmentInForeignEntityMember" xlink:label="InvestmentInForeignEntityMember" xlink:title="InvestmentInForeignEntityMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="InvestmentDomain" xlink:to="InvestmentInForeignEntityMember" xlink:title="definition: InvestmentDomain to InvestmentInForeignEntityMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementGeographicalAxis" xlink:label="StatementGeographicalAxis" xlink:title="StatementGeographicalAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfInvestmentsTable" xlink:to="StatementGeographicalAxis" xlink:title="definition: ScheduleOfInvestmentsTable to StatementGeographicalAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="SegmentGeographicalDomain" xlink:title="SegmentGeographicalDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementGeographicalAxis" xlink:to="SegmentGeographicalDomain" xlink:title="definition: StatementGeographicalAxis to SegmentGeographicalDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="SegmentGeographicalDomain_2" xlink:title="SegmentGeographicalDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementGeographicalAxis" xlink:to="SegmentGeographicalDomain_2" xlink:title="definition: StatementGeographicalAxis to SegmentGeographicalDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/country/2016/country-2016-01-31.xsd#country_TW" xlink:label="TW" xlink:title="TW" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="TW" xlink:title="definition: SegmentGeographicalDomain to TW" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://photronics.com/role/ScheduleIivaluationAndQualifyingAccountsDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ValuationAndQualifyingAccountsDisclosureLineItems" xlink:label="ValuationAndQualifyingAccountsDisclosureLineItems" xlink:title="ValuationAndQualifyingAccountsDisclosureLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MovementInValuationAllowancesAndReservesRollForward" xlink:label="MovementInValuationAllowancesAndReservesRollForward" xlink:title="MovementInValuationAllowancesAndReservesRollForward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ValuationAndQualifyingAccountsDisclosureLineItems" xlink:to="MovementInValuationAllowancesAndReservesRollForward" xlink:title="definition: ValuationAndQualifyingAccountsDisclosureLineItems to MovementInValuationAllowancesAndReservesRollForward" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ValuationAllowancesAndReservesBalance" xlink:label="ValuationAllowancesAndReservesBalance" xlink:title="ValuationAllowancesAndReservesBalance" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ValuationAndQualifyingAccountsDisclosureLineItems" xlink:to="ValuationAllowancesAndReservesBalance" xlink:title="definition: ValuationAndQualifyingAccountsDisclosureLineItems to ValuationAllowancesAndReservesBalance" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense" xlink:label="ValuationAllowancesAndReservesChargedToCostAndExpense" xlink:title="ValuationAllowancesAndReservesChargedToCostAndExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ValuationAndQualifyingAccountsDisclosureLineItems" xlink:to="ValuationAllowancesAndReservesChargedToCostAndExpense" xlink:title="definition: ValuationAndQualifyingAccountsDisclosureLineItems to ValuationAllowancesAndReservesChargedToCostAndExpense" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ValuationAllowancesAndReservesDeductions" xlink:label="ValuationAllowancesAndReservesDeductions" xlink:title="ValuationAllowancesAndReservesDeductions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ValuationAndQualifyingAccountsDisclosureLineItems" xlink:to="ValuationAllowancesAndReservesDeductions" xlink:title="definition: ValuationAndQualifyingAccountsDisclosureLineItems to ValuationAllowancesAndReservesDeductions" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ValuationAndQualifyingAccountsDisclosureTable" xlink:label="ValuationAndQualifyingAccountsDisclosureTable" xlink:title="ValuationAndQualifyingAccountsDisclosureTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ValuationAndQualifyingAccountsDisclosureLineItems" xlink:to="ValuationAndQualifyingAccountsDisclosureTable" xlink:title="definition: ValuationAndQualifyingAccountsDisclosureLineItems to ValuationAndQualifyingAccountsDisclosureTable" order="5.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ValuationAllowancesAndReservesTypeAxis" xlink:label="ValuationAllowancesAndReservesTypeAxis" xlink:title="ValuationAllowancesAndReservesTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ValuationAndQualifyingAccountsDisclosureTable" xlink:to="ValuationAllowancesAndReservesTypeAxis" xlink:title="definition: ValuationAndQualifyingAccountsDisclosureTable to ValuationAllowancesAndReservesTypeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ValuationAllowancesAndReservesDomain" xlink:label="ValuationAllowancesAndReservesDomain" xlink:title="ValuationAllowancesAndReservesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ValuationAllowancesAndReservesTypeAxis" xlink:to="ValuationAllowancesAndReservesDomain" xlink:title="definition: ValuationAllowancesAndReservesTypeAxis to ValuationAllowancesAndReservesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ValuationAllowancesAndReservesDomain" xlink:label="ValuationAllowancesAndReservesDomain_2" xlink:title="ValuationAllowancesAndReservesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ValuationAllowancesAndReservesTypeAxis" xlink:to="ValuationAllowancesAndReservesDomain_2" xlink:title="definition: ValuationAllowancesAndReservesTypeAxis to ValuationAllowancesAndReservesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsMember" xlink:label="AllowanceForDoubtfulAccountsMember" xlink:title="AllowanceForDoubtfulAccountsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ValuationAllowancesAndReservesDomain" xlink:to="AllowanceForDoubtfulAccountsMember" xlink:title="definition: ValuationAllowancesAndReservesDomain to AllowanceForDoubtfulAccountsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ValuationAllowanceOfDeferredTaxAssetsMember" xlink:label="ValuationAllowanceOfDeferredTaxAssetsMember" xlink:title="ValuationAllowanceOfDeferredTaxAssetsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ValuationAllowancesAndReservesDomain" xlink:to="ValuationAllowanceOfDeferredTaxAssetsMember" xlink:title="definition: ValuationAllowancesAndReservesDomain to ValuationAllowanceOfDeferredTaxAssetsMember" order="2.0" />
  </link:definitionLink>
</link:linkbase>




