Lewis & Short

aeternābĭlis, e, adj. [aeterno], that can last forever, everlasting: divitia, Att. ap. Non. 475, 24 (Trag. Rel. p. 143 Rib.): urbs, i. e. Rome, Cod. Th. 11, 20, 3 (cf. aeternus, II. A.).