In the anthropological study of
kinship, a
Moiety is a descent group that coexists with only one other descent group within a
society. In such cases the community usually has
unilineal descent, either patri or matrilineal so that any individual belongs to one of the two moiety groups by birth, and all
marriages take place between members of different moieties. In the case of a patrilineal descent system this can be interpreted as a system in which women are exchanged between the two moieties. Moiety societies are found particularly among the
indigenous cultures of North America and
Australia.