A name that is particularly fitting or appropriate for a person or thing, often reflecting their true nature or characteristics.
From Greek eu- (well, good) + onyma (name). Coined to describe names that seem perfectly suited to their bearers, opposite of misnomer.
There's a real phenomenon called 'nominative determinism' where people unconsciously live up to their names—a person named Joy might genuinely be more cheerful, making euonyms a weird intersection of language and psychology.
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