The term wife is most commonly applied to a woman in a union sanctioned by law (including religious law), but not to a woman in an informal cohabitation relationship, which may be
a combining form of wife, now unproductive, occurring in words that designate traditional roles or occupations of women: fishwife; goodwife; housewife; midwife.
There are 15 meanings listed in OED's entry for the noun wife, one of which is labelled obsolete. See ‘Meaning & use’ for definitions, usage, and quotation evidence.
a combining form of wife, now unproductive, occurring in compound words that in general designate traditional roles or occupations of women: fishwife; housewife; midwife.
from The American Heritage® Dictionary of the English Language, 5th Edition. noun A woman joined to another person in marriage; a female spouse. from The Century Dictionary. To ta