<?xml version="1.0" encoding="utf-8"?>
<linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.xbrl.org/2003/linkbase">
  <roleRef roleURI="http://www.esma.europa.eu/xbrl/role/cor/esef_role-999999" xlink:href="http://www.esma.europa.eu/taxonomy/2020-03-16/esef_cor.xsd#esef_role-999999" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" />
  <roleRef roleURI="http://seniorplc.com/xbrl/2021/roles/Anchoring" xlink:href="5493002hqhwn5jqhkq51-2021-12-31.xsd#Anchoring" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" />
  <roleRef roleURI="http://seniorplc.com/xbrl/2021/roles/StatementOfChangesInEquity" xlink:href="5493002hqhwn5jqhkq51-2021-12-31.xsd#StatementOfChangesInEquity" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" />
  <arcroleRef arcroleURI="http://www.esma.europa.eu/xbrl/esef/arcrole/wider-narrower" xlink:href="http://www.xbrl.org/lrr/arcrole/esma-arcrole-2018-11-21.xsd#wider-narrower" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" />
  <definitionLink xlink:role="http://www.esma.europa.eu/xbrl/role/cor/esef_role-999999" xlink:type="extended" xmlns:xlink="http://www.w3.org/1999/xlink">
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_NoncurrentAssets" xlink:label="ifrs-full_NoncurrentAssets" />
    <loc xlink:type="locator" xlink:href="5493002hqhwn5jqhkq51-2021-12-31.xsd#seniorplc_AdjustedAndDilutedEarningsLossPerShare" xlink:label="seniorplc_AdjustedAndDilutedEarningsLossPerShare" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_NoncurrentLiabilities" xlink:label="ifrs-full_NoncurrentLiabilities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_BasicEarningsLossPerShare" xlink:label="ifrs-full_BasicEarningsLossPerShare" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_NoncurrentProvisions" xlink:label="ifrs-full_NoncurrentProvisions" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_AddressOfRegisteredOfficeOfEntity" xlink:label="ifrs-full_AddressOfRegisteredOfficeOfEntity" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CurrentProvisions" xlink:label="ifrs-full_CurrentProvisions" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_IncomeTaxExpenseContinuingOperations" xlink:label="ifrs-full_IncomeTaxExpenseContinuingOperations" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CashAndCashEquivalentsIfDifferentFromStatementOfFinancialPosition" xlink:label="ifrs-full_CashAndCashEquivalentsIfDifferentFromStatementOfFinancialPosition" />
    <loc xlink:type="locator" xlink:href="5493002hqhwn5jqhkq51-2021-12-31.xsd#seniorplc_CorporateUndertakings" xlink:label="seniorplc_CorporateUndertakings" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_OtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLossNetOfTax" xlink:label="ifrs-full_OtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLossNetOfTax" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_DividendsPaidClassifiedAsFinancingActivities" xlink:label="ifrs-full_DividendsPaidClassifiedAsFinancingActivities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CashAndCashEquivalents" xlink:label="ifrs-full_CashAndCashEquivalents" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_DescriptionOfNatureOfEntitysOperationsAndPrincipalActivities" xlink:label="ifrs-full_DescriptionOfNatureOfEntitysOperationsAndPrincipalActivities" />
    <loc xlink:type="locator" xlink:href="5493002hqhwn5jqhkq51-2021-12-31.xsd#seniorplc_HedgingAndTranslationReserve" xlink:label="seniorplc_HedgingAndTranslationReserve" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CurrentLeaseLiabilities" xlink:label="ifrs-full_CurrentLeaseLiabilities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_DeferredTaxAssets" xlink:label="ifrs-full_DeferredTaxAssets" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CurrentLiabilities" xlink:label="ifrs-full_CurrentLiabilities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_InterestReceivedClassifiedAsInvestingActivities" xlink:label="ifrs-full_InterestReceivedClassifiedAsInvestingActivities" />
    <loc xlink:type="locator" xlink:href="5493002hqhwn5jqhkq51-2021-12-31.xsd#seniorplc_AdjustedEarningsLossPerShare" xlink:label="seniorplc_AdjustedEarningsLossPerShare" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_PaymentsOfLeaseLiabilitiesClassifiedAsFinancingActivities" xlink:label="ifrs-full_PaymentsOfLeaseLiabilitiesClassifiedAsFinancingActivities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_Inventories" xlink:label="ifrs-full_Inventories" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_NoncurrentReceivables" xlink:label="ifrs-full_NoncurrentReceivables" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_DeferredTaxLiabilities" xlink:label="ifrs-full_DeferredTaxLiabilities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_Goodwill" xlink:label="ifrs-full_Goodwill" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ReclassificationAdjustmentsOnCashFlowHedgesBeforeTax" xlink:label="ifrs-full_ReclassificationAdjustmentsOnCashFlowHedgesBeforeTax" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CashFlowsFromUsedInFinancingActivities" xlink:label="ifrs-full_CashFlowsFromUsedInFinancingActivities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_IncomeTaxRelatingToComponentsOfOtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLoss" xlink:label="ifrs-full_IncomeTaxRelatingToComponentsOfOtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLoss" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax" xlink:label="ifrs-full_OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ShareOfProfitLossOfJointVenturesAccountedForUsingEquityMethod" xlink:label="ifrs-full_ShareOfProfitLossOfJointVenturesAccountedForUsingEquityMethod" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_TreasuryShares" xlink:label="ifrs-full_TreasuryShares" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CashFlowsFromUsedInInvestingActivities" xlink:label="ifrs-full_CashFlowsFromUsedInInvestingActivities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_EffectOfExchangeRateChangesOnCashAndCashEquivalents" xlink:label="ifrs-full_EffectOfExchangeRateChangesOnCashAndCashEquivalents" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_IntangibleAssetsOtherThanGoodwill" xlink:label="ifrs-full_IntangibleAssetsOtherThanGoodwill" />
    <loc xlink:type="locator" xlink:href="5493002hqhwn5jqhkq51-2021-12-31.xsd#seniorplc_ProceedsOnDisposalActivitiesNetOfCashBalancesClassifiedAsInvestingActivities" xlink:label="seniorplc_ProceedsOnDisposalActivitiesNetOfCashBalancesClassifiedAsInvestingActivities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_NoncurrentRecognisedLiabilitiesDefinedBenefitPlan" xlink:label="ifrs-full_NoncurrentRecognisedLiabilitiesDefinedBenefitPlan" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_Revenue" xlink:label="ifrs-full_Revenue" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ComprehensiveIncomeAttributableToOwnersOfParent" xlink:label="ifrs-full_ComprehensiveIncomeAttributableToOwnersOfParent" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_PropertyPlantAndEquipment" xlink:label="ifrs-full_PropertyPlantAndEquipment" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_TradingIncomeExpense" xlink:label="ifrs-full_TradingIncomeExpense" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_NoncurrentLeaseLiabilities" xlink:label="ifrs-full_NoncurrentLeaseLiabilities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ProfitLossBeforeTax" xlink:label="ifrs-full_ProfitLossBeforeTax" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_SharePremium" xlink:label="ifrs-full_SharePremium" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ProfitLossAttributableToOwnersOfParent" xlink:label="ifrs-full_ProfitLossAttributableToOwnersOfParent" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_InvestmentsInJointVentures" xlink:label="ifrs-full_InvestmentsInJointVentures" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_DilutedEarningsLossPerShare" xlink:label="ifrs-full_DilutedEarningsLossPerShare" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_InvestmentIncome" xlink:label="ifrs-full_InvestmentIncome" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_FinanceCosts" xlink:label="ifrs-full_FinanceCosts" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_RetainedEarnings" xlink:label="ifrs-full_RetainedEarnings" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_PurchaseOfPropertyPlantAndEquipmentClassifiedAsInvestingActivities" xlink:label="ifrs-full_PurchaseOfPropertyPlantAndEquipmentClassifiedAsInvestingActivities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_IssuedCapital" xlink:label="ifrs-full_IssuedCapital" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_Liabilities" xlink:label="ifrs-full_Liabilities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CurrentAssets" xlink:label="ifrs-full_CurrentAssets" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_PurchaseOfIntangibleAssetsClassifiedAsInvestingActivities" xlink:label="ifrs-full_PurchaseOfIntangibleAssetsClassifiedAsInvestingActivities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_OtherComprehensiveIncome" xlink:label="ifrs-full_OtherComprehensiveIncome" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ProceedsFromSalesOfPropertyPlantAndEquipmentClassifiedAsInvestingActivities" xlink:label="ifrs-full_ProceedsFromSalesOfPropertyPlantAndEquipmentClassifiedAsInvestingActivities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_NameOfReportingEntityOrOtherMeansOfIdentification" xlink:label="ifrs-full_NameOfReportingEntityOrOtherMeansOfIdentification" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CountryOfIncorporation" xlink:label="ifrs-full_CountryOfIncorporation" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_NoncurrentRecognisedAssetsDefinedBenefitPlan" xlink:label="ifrs-full_NoncurrentRecognisedAssetsDefinedBenefitPlan" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_GainsLossesOnCashFlowHedgesBeforeTax" xlink:label="ifrs-full_GainsLossesOnCashFlowHedgesBeforeTax" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CashFlowsFromUsedInOperatingActivities" xlink:label="ifrs-full_CashFlowsFromUsedInOperatingActivities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ProfitLossFromOperatingActivities" xlink:label="ifrs-full_ProfitLossFromOperatingActivities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_NetAssetsLiabilities" xlink:label="ifrs-full_NetAssetsLiabilities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_RepaymentsOfBorrowingsClassifiedAsFinancingActivities" xlink:label="ifrs-full_RepaymentsOfBorrowingsClassifiedAsFinancingActivities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_IncreaseDecreaseInCashAndCashEquivalentsBeforeEffectOfExchangeRateChanges" xlink:label="ifrs-full_IncreaseDecreaseInCashAndCashEquivalentsBeforeEffectOfExchangeRateChanges" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_EquityAttributableToOwnersOfParent" xlink:label="ifrs-full_EquityAttributableToOwnersOfParent" />
    <loc xlink:type="locator" xlink:href="http://www.esma.europa.eu/taxonomy/2020-03-16/esef_cor.xsd#esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:label="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_TradeAndOtherCurrentPayables" xlink:label="ifrs-full_TradeAndOtherCurrentPayables" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ReserveOfSharebasedPayments" xlink:label="ifrs-full_ReserveOfSharebasedPayments" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CurrentTaxAssets" xlink:label="ifrs-full_CurrentTaxAssets" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_LegalFormOfEntity" xlink:label="ifrs-full_LegalFormOfEntity" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ProceedsFromBorrowingsClassifiedAsFinancingActivities" xlink:label="ifrs-full_ProceedsFromBorrowingsClassifiedAsFinancingActivities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_Assets" xlink:label="ifrs-full_Assets" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_OtherNoncurrentLiabilities" xlink:label="ifrs-full_OtherNoncurrentLiabilities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_LongtermBorrowings" xlink:label="ifrs-full_LongtermBorrowings" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CurrentTaxLiabilities" xlink:label="ifrs-full_CurrentTaxLiabilities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_TradeAndOtherCurrentReceivables" xlink:label="ifrs-full_TradeAndOtherCurrentReceivables" />
    <loc xlink:type="locator" xlink:href="5493002hqhwn5jqhkq51-2021-12-31.xsd#seniorplc_AdjustedLossBeforeTax" xlink:label="seniorplc_AdjustedLossBeforeTax" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_IncomeTaxRelatingToComponentsOfOtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLoss" xlink:label="ifrs-full_IncomeTaxRelatingToComponentsOfOtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLoss" />
    <loc xlink:type="locator" xlink:href="5493002hqhwn5jqhkq51-2021-12-31.xsd#seniorplc_AdjustedOperatingProfit" xlink:label="seniorplc_AdjustedOperatingProfit" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ShorttermBorrowings" xlink:label="ifrs-full_ShorttermBorrowings" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_NameOfReportingEntityOrOtherMeansOfIdentification" order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_DescriptionOfNatureOfEntitysOperationsAndPrincipalActivities" order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_Revenue" order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_TradingIncomeExpense" order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_ShareOfProfitLossOfJointVenturesAccountedForUsingEquityMethod" order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_ProfitLossFromOperatingActivities" order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_InvestmentIncome" order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_FinanceCosts" order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="seniorplc_CorporateUndertakings" order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_ProfitLossBeforeTax" order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_IncomeTaxExpenseContinuingOperations" order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_ProfitLossAttributableToOwnersOfParent" order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_BasicEarningsLossPerShare" order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_DilutedEarningsLossPerShare" order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="seniorplc_AdjustedOperatingProfit" order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="seniorplc_AdjustedLossBeforeTax" order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="seniorplc_AdjustedEarningsLossPerShare" order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="seniorplc_AdjustedAndDilutedEarningsLossPerShare" order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_GainsLossesOnCashFlowHedgesBeforeTax" order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_ReclassificationAdjustmentsOnCashFlowHedgesBeforeTax" order="20" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_IncomeTaxRelatingToComponentsOfOtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLoss" order="21" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax" order="22" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_IncomeTaxRelatingToComponentsOfOtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLoss" order="23" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_OtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLossNetOfTax" order="24" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_OtherComprehensiveIncome" order="25" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_ComprehensiveIncomeAttributableToOwnersOfParent" order="26" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_Goodwill" order="27" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_IntangibleAssetsOtherThanGoodwill" order="28" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_InvestmentsInJointVentures" order="29" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_PropertyPlantAndEquipment" order="30" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_DeferredTaxAssets" order="31" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_NoncurrentRecognisedAssetsDefinedBenefitPlan" order="32" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_NoncurrentReceivables" order="33" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_NoncurrentAssets" order="34" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_Inventories" order="35" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_CurrentTaxAssets" order="36" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_TradeAndOtherCurrentReceivables" order="37" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_CashAndCashEquivalents" order="38" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_CurrentAssets" order="39" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_Assets" order="40" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_TradeAndOtherCurrentPayables" order="41" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_CurrentTaxLiabilities" order="42" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_CurrentLeaseLiabilities" order="43" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_ShorttermBorrowings" order="44" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_CurrentProvisions" order="45" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_CurrentLiabilities" order="46" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_LongtermBorrowings" order="47" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_NoncurrentRecognisedLiabilitiesDefinedBenefitPlan" order="48" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_DeferredTaxLiabilities" order="49" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_NoncurrentLeaseLiabilities" order="50" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_NoncurrentProvisions" order="51" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_OtherNoncurrentLiabilities" order="52" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_NoncurrentLiabilities" order="53" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_Liabilities" order="54" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_NetAssetsLiabilities" order="55" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_IssuedCapital" order="56" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_SharePremium" order="57" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_ReserveOfSharebasedPayments" order="58" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="seniorplc_HedgingAndTranslationReserve" order="59" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_RetainedEarnings" order="60" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_TreasuryShares" order="61" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_EquityAttributableToOwnersOfParent" order="62" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_CashFlowsFromUsedInOperatingActivities" order="63" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_InterestReceivedClassifiedAsInvestingActivities" order="64" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_ProceedsFromSalesOfPropertyPlantAndEquipmentClassifiedAsInvestingActivities" order="65" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_PurchaseOfPropertyPlantAndEquipmentClassifiedAsInvestingActivities" order="66" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_PurchaseOfIntangibleAssetsClassifiedAsInvestingActivities" order="67" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="seniorplc_ProceedsOnDisposalActivitiesNetOfCashBalancesClassifiedAsInvestingActivities" order="68" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_CashFlowsFromUsedInInvestingActivities" order="69" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_DividendsPaidClassifiedAsFinancingActivities" order="70" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_ProceedsFromBorrowingsClassifiedAsFinancingActivities" order="71" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_RepaymentsOfBorrowingsClassifiedAsFinancingActivities" order="72" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_PaymentsOfLeaseLiabilitiesClassifiedAsFinancingActivities" order="73" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_CashFlowsFromUsedInFinancingActivities" order="74" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_IncreaseDecreaseInCashAndCashEquivalentsBeforeEffectOfExchangeRateChanges" order="75" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_CashAndCashEquivalentsIfDifferentFromStatementOfFinancialPosition" order="76" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_EffectOfExchangeRateChangesOnCashAndCashEquivalents" order="77" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_LegalFormOfEntity" order="78" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_CountryOfIncorporation" order="79" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="esef_cor_LineItemsNotDimensionallyQualifiedPlaceholder" xlink:to="ifrs-full_AddressOfRegisteredOfficeOfEntity" order="80" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
  </definitionLink>
  <definitionLink xlink:role="http://seniorplc.com/xbrl/2021/roles/Anchoring" xlink:type="extended" xmlns:xlink="http://www.w3.org/1999/xlink">
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ProfitLossFromOperatingActivities" xlink:label="ifrs-full_ProfitLossFromOperatingActivities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_BasicAndDilutedEarningsLossPerShare" xlink:label="ifrs-full_BasicAndDilutedEarningsLossPerShare" />
    <loc xlink:type="locator" xlink:href="5493002hqhwn5jqhkq51-2021-12-31.xsd#seniorplc_ProceedsOnDisposalActivitiesNetOfCashBalancesClassifiedAsInvestingActivities" xlink:label="seniorplc_ProceedsOnDisposalActivitiesNetOfCashBalancesClassifiedAsInvestingActivities" />
    <loc xlink:type="locator" xlink:href="5493002hqhwn5jqhkq51-2021-12-31.xsd#seniorplc_TransferToRetainedEarnings" xlink:label="seniorplc_TransferToRetainedEarnings" />
    <loc xlink:type="locator" xlink:href="5493002hqhwn5jqhkq51-2021-12-31.xsd#seniorplc_AdjustedLossBeforeTax" xlink:label="seniorplc_AdjustedLossBeforeTax" />
    <loc xlink:type="locator" xlink:href="5493002hqhwn5jqhkq51-2021-12-31.xsd#seniorplc_AdjustedEarningsLossPerShare" xlink:label="seniorplc_AdjustedEarningsLossPerShare" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_EquityAttributableToOwnersOfParent" xlink:label="ifrs-full_EquityAttributableToOwnersOfParent" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ChangesInEquity" xlink:label="ifrs-full_ChangesInEquity" />
    <loc xlink:type="locator" xlink:href="5493002hqhwn5jqhkq51-2021-12-31.xsd#seniorplc_CorporateUndertakings" xlink:label="seniorplc_CorporateUndertakings" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_BasicEarningsLossPerShare" xlink:label="ifrs-full_BasicEarningsLossPerShare" />
    <loc xlink:type="locator" xlink:href="5493002hqhwn5jqhkq51-2021-12-31.xsd#seniorplc_AdjustedAndDilutedEarningsLossPerShare" xlink:label="seniorplc_AdjustedAndDilutedEarningsLossPerShare" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ReserveOfCashFlowHedges" xlink:label="ifrs-full_ReserveOfCashFlowHedges" />
    <loc xlink:type="locator" xlink:href="5493002hqhwn5jqhkq51-2021-12-31.xsd#seniorplc_AdjustedOperatingProfit" xlink:label="seniorplc_AdjustedOperatingProfit" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ProfitLossBeforeTax" xlink:label="ifrs-full_ProfitLossBeforeTax" />
    <loc xlink:type="locator" xlink:href="5493002hqhwn5jqhkq51-2021-12-31.xsd#seniorplc_HedgingAndTranslationReserve" xlink:label="seniorplc_HedgingAndTranslationReserve" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CashFlowsFromUsedInInvestingActivities" xlink:label="ifrs-full_CashFlowsFromUsedInInvestingActivities" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ReserveOfExchangeDifferencesOnTranslation" xlink:label="ifrs-full_ReserveOfExchangeDifferencesOnTranslation" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_ProfitLossBeforeTax" xlink:to="seniorplc_CorporateUndertakings" order="1" xlink:arcrole="http://www.esma.europa.eu/xbrl/esef/arcrole/wider-narrower" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_ProfitLossFromOperatingActivities" xlink:to="seniorplc_AdjustedOperatingProfit" order="1" xlink:arcrole="http://www.esma.europa.eu/xbrl/esef/arcrole/wider-narrower" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_ProfitLossBeforeTax" xlink:to="seniorplc_AdjustedLossBeforeTax" order="1" xlink:arcrole="http://www.esma.europa.eu/xbrl/esef/arcrole/wider-narrower" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_BasicEarningsLossPerShare" xlink:to="seniorplc_AdjustedEarningsLossPerShare" order="1" xlink:arcrole="http://www.esma.europa.eu/xbrl/esef/arcrole/wider-narrower" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_BasicAndDilutedEarningsLossPerShare" xlink:to="seniorplc_AdjustedAndDilutedEarningsLossPerShare" order="1" xlink:arcrole="http://www.esma.europa.eu/xbrl/esef/arcrole/wider-narrower" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="seniorplc_HedgingAndTranslationReserve" xlink:to="ifrs-full_ReserveOfCashFlowHedges" order="1" xlink:arcrole="http://www.esma.europa.eu/xbrl/esef/arcrole/wider-narrower" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="seniorplc_HedgingAndTranslationReserve" xlink:to="ifrs-full_ReserveOfExchangeDifferencesOnTranslation" order="2" xlink:arcrole="http://www.esma.europa.eu/xbrl/esef/arcrole/wider-narrower" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_EquityAttributableToOwnersOfParent" xlink:to="seniorplc_HedgingAndTranslationReserve" order="3" xlink:arcrole="http://www.esma.europa.eu/xbrl/esef/arcrole/wider-narrower" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_ChangesInEquity" xlink:to="seniorplc_TransferToRetainedEarnings" order="1" xlink:arcrole="http://www.esma.europa.eu/xbrl/esef/arcrole/wider-narrower" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_CashFlowsFromUsedInInvestingActivities" xlink:to="seniorplc_ProceedsOnDisposalActivitiesNetOfCashBalancesClassifiedAsInvestingActivities" order="1" xlink:arcrole="http://www.esma.europa.eu/xbrl/esef/arcrole/wider-narrower" priority="1" />
  </definitionLink>
  <definitionLink xlink:role="http://seniorplc.com/xbrl/2021/roles/StatementOfChangesInEquity" xlink:type="extended" xmlns:xlink="http://www.w3.org/1999/xlink">
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ReserveOfExchangeDifferencesOnTranslationMember" xlink:label="ifrs-full_ReserveOfExchangeDifferencesOnTranslationMember" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_IncreaseDecreaseThroughSharebasedPaymentTransactions" xlink:label="ifrs-full_IncreaseDecreaseThroughSharebasedPaymentTransactions" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_StatementOfChangesInEquityAbstract" xlink:label="ifrs-full_StatementOfChangesInEquityAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_DividendsPaid" xlink:label="ifrs-full_DividendsPaid" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_TreasurySharesMember" xlink:label="ifrs-full_TreasurySharesMember" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_OtherComprehensiveIncomeBeforeTaxCashFlowHedges" xlink:label="ifrs-full_OtherComprehensiveIncomeBeforeTaxCashFlowHedges" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_IncomeTaxRelatingToComponentsOfOtherComprehensiveIncome" xlink:label="ifrs-full_IncomeTaxRelatingToComponentsOfOtherComprehensiveIncome" />
    <loc xlink:type="locator" xlink:href="5493002hqhwn5jqhkq51-2021-12-31.xsd#seniorplc_TransferToRetainedEarnings" xlink:label="seniorplc_TransferToRetainedEarnings" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ReserveOfSharebasedPaymentsMember" xlink:label="ifrs-full_ReserveOfSharebasedPaymentsMember" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ComprehensiveIncome" xlink:label="ifrs-full_ComprehensiveIncome" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ReserveOfCashFlowHedgesMember" xlink:label="ifrs-full_ReserveOfCashFlowHedgesMember" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ProfitLoss" xlink:label="ifrs-full_ProfitLoss" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_RetainedEarningsMember" xlink:label="ifrs-full_RetainedEarningsMember" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_IssuedCapitalMember" xlink:label="ifrs-full_IssuedCapitalMember" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_PurchaseOfTreasuryShares" xlink:label="ifrs-full_PurchaseOfTreasuryShares" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_Equity" xlink:label="ifrs-full_Equity" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_SharePremiumMember" xlink:label="ifrs-full_SharePremiumMember" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ReclassificationAdjustmentsOnExchangeDifferencesOnTranslationBeforeTax" xlink:label="ifrs-full_ReclassificationAdjustmentsOnExchangeDifferencesOnTranslationBeforeTax" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_OtherComprehensiveIncomeBeforeTaxGainsLossesOnRemeasurementsOfDefinedBenefitPlans" xlink:label="ifrs-full_OtherComprehensiveIncomeBeforeTaxGainsLossesOnRemeasurementsOfDefinedBenefitPlans" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_GainsLossesOnExchangeDifferencesOnTranslationBeforeTax" xlink:label="ifrs-full_GainsLossesOnExchangeDifferencesOnTranslationBeforeTax" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_IncreaseDecreaseThroughExerciseOfOptions" xlink:label="ifrs-full_IncreaseDecreaseThroughExerciseOfOptions" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ComponentsOfEquityAxis" xlink:label="ifrs-full_ComponentsOfEquityAxis" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_StatementOfChangesInEquityTable" xlink:label="ifrs-full_StatementOfChangesInEquityTable" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_DecreaseIncreaseThroughTaxOnSharebasedPaymentTransactions" xlink:label="ifrs-full_DecreaseIncreaseThroughTaxOnSharebasedPaymentTransactions" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_EquityMember" xlink:label="ifrs-full_EquityMember" />
    <loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_StatementOfChangesInEquityLineItems" xlink:label="ifrs-full_StatementOfChangesInEquityLineItems" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_StatementOfChangesInEquityAbstract" xlink:to="ifrs-full_StatementOfChangesInEquityTable" order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" priority="1" xbrldt:contextElement="scenario" xbrldt:closed="true" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_StatementOfChangesInEquityTable" xlink:to="ifrs-full_ComponentsOfEquityAxis" order="0" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_ComponentsOfEquityAxis" xlink:to="ifrs-full_EquityMember" order="0" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_EquityMember" xlink:to="ifrs-full_IssuedCapitalMember" order="0" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_EquityMember" xlink:to="ifrs-full_ReserveOfCashFlowHedgesMember" order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_EquityMember" xlink:to="ifrs-full_ReserveOfExchangeDifferencesOnTranslationMember" order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_EquityMember" xlink:to="ifrs-full_ReserveOfSharebasedPaymentsMember" order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_EquityMember" xlink:to="ifrs-full_RetainedEarningsMember" order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_EquityMember" xlink:to="ifrs-full_SharePremiumMember" order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_EquityMember" xlink:to="ifrs-full_TreasurySharesMember" order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_StatementOfChangesInEquityAbstract" xlink:to="ifrs-full_StatementOfChangesInEquityLineItems" order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_Equity" order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_ProfitLoss" order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_OtherComprehensiveIncomeBeforeTaxCashFlowHedges" order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_ReclassificationAdjustmentsOnExchangeDifferencesOnTranslationBeforeTax" order="25" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_GainsLossesOnExchangeDifferencesOnTranslationBeforeTax" order="33" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_OtherComprehensiveIncomeBeforeTaxGainsLossesOnRemeasurementsOfDefinedBenefitPlans" order="41" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_IncomeTaxRelatingToComponentsOfOtherComprehensiveIncome" order="49" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_ComprehensiveIncome" order="57" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_IncreaseDecreaseThroughSharebasedPaymentTransactions" order="65" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_DecreaseIncreaseThroughTaxOnSharebasedPaymentTransactions" order="73" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_PurchaseOfTreasuryShares" order="81" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_IncreaseDecreaseThroughExerciseOfOptions" order="89" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="seniorplc_TransferToRetainedEarnings" order="97" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
    <definitionArc xlink:type="arc" xlink:from="ifrs-full_StatementOfChangesInEquityLineItems" xlink:to="ifrs-full_DividendsPaid" order="105" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" priority="1" />
  </definitionLink>
</linkbase>