Lewis & Short

Genāva (less correctly Genna or Genēva), ae, f., a city of the Allobroges, upon Lake Leman, at the point where the Rhone passes from it, Geneva, Caes. B. G. 1, 6, 3; 1, 7, 1 sq.
Deriv.: Genāven-sis (Genēv-), e, of Geneva, Inscr. Orell. 253; called Genevensis, ib. 254.