Kin Groups and Descent. The concept of tabinaw governs Yapese thinking about family, kinship, and social Organization. In its primary reference, tabinaw refers to the Household or nuclear family. However, each nuclear family is part of an estate group, comprised of adult men and women who hold common rights to land and who share resources and labor in reference to exploitation of this land. An estate group may include three or four generations of men with their wives and children. Each married couple will have a separate household located on estate land. Yapese practice a variation of double descent. Every individual has a matrilineal kinship affiliation, termed genung, which plays a predominant role in the definition of sibling relationships and the identification of kin ties for mutual support and assistance. In Yapese thought, one obtains one's blood relationship through one's mother. In addition to this matrilineal principle, Yapese trace their spiritual and subsistence relationships to the land through their fathers. Each Yapese receives a name from one of his or her patrilineally related ancestors who have occupied the land estate upon which he or she is born and nurtured. The ancestral line of land and nurture comes through the patrilineally inherited estate. The matrilineal principle does not define significant descent groups on Yap, but only an affiliation of kin to whom one relates to serve significant individual interests. The estate group is formed more appropriately in terms of relationship to land than in terms of patrilineal Descent. With these qualifications we may speak of double Descent on Yap.
Kinship Terminology. Traditionally Yapese have a Crow-type pattern of cousin terminology. In the present younger generation, a Hawaiian-type pattern is emerging as the dominant pattern of kinship classification, complicated further by the introduction of English cousin terminology in schools.