clan

Social grouping based on kinship. Some traditional societies are organized by clans, which are either matrilineal or patrilineal, and whose members must marry into another clan in order to avoid in‐breeding.

Familiar examples are the Highland clans of Scotland. Theoretically each clan is descended from a single ancestor from whom the name is derived – for example, clan MacGregor (‘son of Gregor’).

Clans played a large role in the Jacobite revolts of 1715 and 1745, after which their individual tartan Highland dress was banned 1746–82. Rivalry between them was often bitter.