A division of a society into two distinct social categories or groups, often on the basis of descent; one of two basic complementary tribal subdivisions. Moieties are groups that are exogamous (i.e., marriage between members of the same moiety is forbidden), of unilineal descent, and in some sense opposed. Sometimes the term moiety is used more loosely to refer simply to one of two divisions of a society, regardless of descent or marriage regulation.