A co-wife in general.
A woman who is simultaneously sister and wife to her spouse.
In a polygamous marriage, a woman who is simultaneously the sister and co-wife of another.
A wife who provides domestic or social support, but not love or affection
Another wife of one's husband. Typically used in cases of divorce and subsequent remarriage for one's husband's ex-wife, but sometimes used in polygamy for a co-wife.
A wife in law only, such as one who has abandoned her husband