A clan is a group of people united by actual or perceived kinship and descent. Even if lineage details are unknown, a clan may claim descent from a founding member or apical ancestor who serves as a symbol of the clan's unity. Clans, in indigenous societies, were not endogamous: their members could not marry one another.

In anthropology, kinship is the web of social relationships that form an important part of the lives of all humans in all societies, although its exact meanings even within this discipline are often debated. Anthropologist Robin Fox says that the study of kinship is the study of what humans do with these basic facts of life – mating, gestation, parenthood, socialization, siblingship etc. Human society is unique, he argues, in that we are "working with the same raw material as exists in the animal world, but [we] can conceptualize and categorize it to serve social ends." These social ends include the socialization of children and the formation of basic economic, political and religious groups.