gens (jĕnz), ancient Roman kinship group. It was the counterpart of what is known in other societies as a patrilineal clan or sib, and the word has been used in social science as a generic term for such groupings. The members of the Roman gens were descended (or assumed to be descended) from a common ancestor, whose name was used by all the members of the group. The second name was the gens name (e.g., Tullius in Marcus Tullius Cicero). The members were united in worship of the common ancestor, and marriage within the gens was discouraged. In early Rome the gens had economic, political, religious, and social functions; it later came to mean little more than a family name. The Greek gens (genos) was similar to the Roman.