Real Dictionary

gens in American English
in ancient Rome, a clan united by descent through the male line from a common ancestor and having both name and religious observances in common
noun: a group of families in ancient Rome claiming descent from a common ancestor and united by a common name and common ancestral religious rites

gens in British English
noun: (in ancient Rome) any of a group of aristocratic families, having a common name and claiming descent from a common ancestor in the male line