Lewis & Short

amnĭcus, a, um, adj. [amnis], of or pertaining to a river (only post-class.): calami, Plin. 16, 36, 66, § 166: insula Metubarris amnicarum maxima, i. e. of those formed by rivers, id. 3, 25, 28, § 148: calami, id. 16, 36, 66, § 166: pisces, Sol. 37: terga, Aus. Mos. 205.