aunt.

From Middle English aunte, from Anglo-Norman aunte, from Old French ante, from Latin amita (“father's sister”). Displaced native Middle English modrie (“aunt”) (from Old English mōdriġe (“maternal aunt”); compare Old English faþu, faþe (“paternal aunt”)). Notes on pronunciation and spelling The digraph ⟨au⟩ representing /æ ~ ɑː/ (rather than /ɔː/) is irregular. It likely reflects a development of Middle English /au̯/ to [aː~æː] before /m n/ in some varieties of Early Modern English, which later came to be identified with either /æ/ or [æː] from pre-fricative lengthening (in the latter case, creating a phoneme /æː/; this is the basis of the bath lexical set). Such pronunciations historically competed with more learned ones where /au̯/ underwent its normal development to /ɔː/, with the standard language eventually adopting /æ ~ ɑː/ in words that came to be spelt with ⟨a⟩ and /ɔː/ in those which came to be spelt with ⟨au⟩ except in this word. However, dialects may have /æ/ or /ɑː/ in other words such as launch, especially in the UK. An alternative explanation derives /æ ~ ɑː/ in this word (and other instances of bath before /m n/) from a collateral Middle English form with /a/, which would've undergone lengthening before nasals analogous to that occuring before fricatives. Though such a collateral form may be ancestral to pronunciations with /a ~ æ/ in some varieties, this hypothesis cannot explain why inherited instances of bath before /m n/ only derive from Middle English words which had variants in /au̯m au̯n/.