Definition of: clan

(klan) noun
1. A united group of relatives, or families, having a common ancestor, one hereditary chieftain, and the same surname, especially in the Scottish Highlands.
2. In certain primitive societies, a body of kindred related in only one line, the members of which do not intermarry, having its own council, property, religion, etc.; an exogamous subdivision of a tribe: also called sib.
3. A clique, or set of persons; a fraternity; club. See synonyms under CLASS. [<Scottish Gaelic clānn]