Kinship is the system of social relationships based on descent and marriage. It organizes who is related to whom, what obligations they owe each other, and how property and status pass between generations. In small-scale societies, kinship is the backbone of social life. It determines where you live, who you marry, who you can joke with, and who will care for you when you are old.

Anthropologists have mapped kinship systems around the world and found remarkable variety. Some societies trace descent only through the mother, others only through the father, and some through both. Marriage rules range from strict exogamy to preferential cousin marriage. Kinship terms can be classificatory, lumping many people under one word, or descriptive, distinguishing each relative precisely.

Core concepts

• Descent: unilineal, bilateral, or double.
• Marriage: exogamy, endogamy, monogamy, polygamy.
• Residence: patrilocal, matrilocal, neolocal.
• Terminology: how a culture classifies relatives.

Kinship is not just about biology. Adoption, godparenthood, and ritual ties can create kin as surely as birth.