þéttar

ættar is an Icelandic-Norse term meaning lineage, family, or descent. In Old Norse and medieval Icelandic texts, ætt denotes a kin group, clan, or noble house, and the plural ættir refers to lineages. The genitive form ættar is used in constructions meaning “of a lineage,” and appears in genealogical writing to situate individuals within kin networks. In sagas and other sources, membership in an ætt could influence status, inheritance, and political alliances, making genealogical ties central to social identity.

The concept of ætt is foundational for understanding Norse and Icelandic kinship and social organization. Many households traced authority and prestige through their lineages, and genealogical knowledge served to establish rights to property, leadership, and alliances. Etymologically, the word derives from Old Norse ǽtt/ætt and has cognates across Scandinavian languages, reflecting a shared notion of descent and family belonging in the medieval Norse world.

In modern Icelandic, ætt survives as the standard word for family or lineage and appears in related terms such as ættfræði (genealogy) and ættbók (genealogical record). The plural form ættir means lineages, while the genitive ættar continues to be used in scholarly and literary contexts to indicate “of a lineage.” Together, ætt and its derivatives remain central to discussions of descent, ancestry, and social history in Icelandic and Norse studies.