noun
(Ancient Rome, historical) A legally defined unit of Roman society, being a collection of people related through a common ancestor by birth, marriage or adoption, possibly over many generations, and sharing the same nomen gentilicium.
(anthropology) A tribal subgroup whose members are characterized by having the same descent, usually along the male line; clan.
(zoology) A host-specific lineage of a brood parasite species.^([W])
noun
plural of gen (clipping of generation).