Lewis & Short

cētus, i, m. (acc. to the Gr. cētŏs, n., Plin. 32, 1, 4, § 10; and hence common in the plur. cētē = κήτη, Verg. A. 5, 822; Plin. 9, 24, 40, § 78; 9, 50, 74, § 157; Sil. 7, 476), = κῆτος,

  1. I. any large sea-animal, a seamonster; particularly a species of whale, a shark, dog-fish, seal, dolphin, etc., Plin. l. l.; Plaut. Aul. 2, 8, 5; id. Capt. 4, 2, 72; Cels. 2, 18.
  2. II. As a constellation, the Whale, Vitr. 9, 7; Manil. 1, 612.