siðr

Siðr is a term found in Old Norse and modern Icelandic that denotes custom, usage, and tradition. It encompasses the patterns of behavior a community considers appropriate, including social norms, etiquette, and ritual practices. While related to law, siðr refers to unwritten, customary expectations that guide conduct in everyday life as well as in ceremonial contexts.

In historical sources, siðr covers a range of practices from hospitality and oath-taking to ritual acts and the conduct expected at gatherings or feasts. It often operates alongside formal legal codes (lög), providing a complementary layer of social obligation that is transmitted orally and reinforced by reputation, kinship ties, and communal sanction. The concept highlights how communities organize themselves through shared norms rather than solely through written statutes.

Siðr also functions as a marker of group identity and continuity, linking generations through inherited practices and stories about proper behavior. Because it is primarily oral and situational, siðr can vary between regions, social groups, and historical periods, reflecting local customs and evolving norms.

In contemporary Icelandic, the modern cognate is siður, meaning custom or tradition. The term siðr appears mainly in scholarly or historical discussions of Norse culture, where it helps describe the moral and ceremonial framework that shaped social life in Viking and medieval Icelandic societies.