People related by blood or marriage; family members or relatives. As an adjective, means similar in kind or having similar characteristics.
From Middle English kinrede, a compound of 'kin' plus the suffix -red (meaning 'condition'). Originally meant the state of being related by blood, then extended to mean the actual relatives themselves, and finally to things that are alike in nature.
The phrase 'kindred spirits' originally had nothing to do with family - it was coined by Anne of Green Gables author L.M. Montgomery to describe people who connect deeply despite not being related! It's become so popular that we've almost forgotten 'kindred' originally just meant your actual cousins.
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