Lewis & Short

Ĕlĕphantīne, ēs, f., = Ἐλεφαντίνη, a small but very fertile island of the Nile, in the Thebaid, with a city of the same name, now Jezyret-Assuan, Mel. 1, 9, 2; 9; Varr. R. R. 1, 7, 6; Tac. A. 2, 61; Plin. 24, 17, 102, § 163.
Also called Elĕphantis, ĭdis, f., Plin. 5, 9, 10, § 59; Vitr. 8, 2, 6.