eponyme

{ } n. [ Cf. F. éponyme. See Eponymous. ] 1. The hypothetical individual who is assumed as the person from whom any race, city, etc., took its name; as, Hellen is an eponym of the Hellenes. [ 1913 Webster ]

2. A name, as of a people, country, and the like, derived from that of an individual. [ 1913 Webster ]