Relevant, pertinent, or closely related to the matter at hand; having a close kinship or connection.
From Old French germain meaning 'having the same parents,' from Latin germanus 'genuine, authentic.' Legal usage developed to mean 'closely related' before extending to 'relevant.'
The phrase 'cousin germain' once meant first cousin, and this family relationship metaphor beautifully captures how ideas can be 'related' - some thoughts are distant relatives, others are siblings.
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