if a society is divided into exactly two descent groups, each is called a moiety, after the french word for "half". if the two halves are each obliged to marry out, and into the other, these are called matrimonial moieties. houseman and white (1998b, bibliography) have discovered numerous societies where kinship network analysis shows that two halves marry one another, similar to matrimonial moieties, except that the two halves—which they call matrimonial "sides"—are neither named nor descent groups, although the egocentric kinship terms may be consistent with the pattern of sidedness, whereas the sidedness is culturally evident but imperfect.