means a married woman, considered in relation to her spouse.

from From Old English 'wif,' which simply meant 'woman' — no marriage required. You can still hear that older sense in 'midwife' (literally 'with-woman,' the one who's with you in childbirth) and in 'woman' itself, which began as 'wifman,' a 'wif-person.' The narrowing from 'any woman' to 'married woman' happened gradually over the medieval centuries. The deeper root is Germanic (compare German 'Weib' and Dutch 'wijf'), but beyond that the trail goes cold — its ultimate origin is genuinely uncertain, with scholars offering guesses but no consensus.