for what reason or purpose; why—often used in older English to ask or explain the cause of something.
From Old English 'hwær' (where) + 'fore' (before/for). Originally meant 'from what place' but evolved to mean 'for what reason' by Middle English. Shakespeare famously used it in 'O Romeo, Romeo, wherefore art thou Romeo?'
Most people think 'wherefore' means 'where' because of that Romeo line, but it actually means 'why'—Romeo's asking why he's Romeo, not where he is! This mix-up shows how language meanings shift and how a single word can trick people 400 years later.
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