kinship, relationship by blood (consanguinity) or marriage (affinity) between persons; also, in anthropology and sociology, a system of rules, based on such relationships, governing descent, inheritance, marriage, extramarital sexual relations, and sometimes residence. All societies recognize consanguineal and affinal ties between individuals, but there is great divergence in the manner of reckoning descent and relationship. Kinship patterns are so specific and elaborate that they constitute an important and independent field of anthropological and sociological investigation. In many societies the concept of kinship extends beyond family ties, which vary in breadth and inclusiveness, to less precisely defined groupings such as the clan, where consanguinity is often hypothetical if not actually mythological. As a rule, however, these groups maintain incest taboos as strict as those for close biological relatives.

Socially recognized relationship between people who are or are held to be biologically related or who are given the status of relatives by marriage, adoption, or other ritual. Kinship is the broad term for all the relationships that people are born into or create later in life that are considered binding in the eyes of society. Every person belongs to a family of orientation (e.g., mother, father, brothers, and sisters); many adults also belong to a family of procreation (which includes a spouse or spouses and children). Familial bonds of descent and marriage may be traced through a genealogy, a written or oral statement of the names of individuals and their kin relations to one another. Inheritance and succession (the transmission of power and position in society) usually follow kinship lines. Seealso exogamy and endogamy; incest.

Learn more about kinship with a free trial on Britannica.com.