出典:Wiktionary
In this context, the word “wives” means “women” and not “married women,” retaining the original sense of 古期英語 wīf, which meant “woman” as well as “wife”. The phrase could be a reformation of 古期英語 ealdra cwēna spell or a calque of Latin anīlis fābula, both literally “old women’s story.”
old wives' tale (複数形 old wives' tales)