"a thing of the same kind as, or nearly allied to, another," 1730s, from French congénère (16c.), from Latin congener "of the same race or kind," from assimilated form of com "with, together" (see con-) + gener-, stem of genus "race, kind" (from PIE root *gene- "give birth, beget," with derivatives referring to procreation and familial and tribal groups). Related: Congenerous (1640s); congeneracy.