Lewis & Short

Cōcȳtus (-ŏs), i, m., = Κωκυτὀς [river of lamentation, from κωκὐω, to howl, weep],

  1. I. a mythic river in the Lower World, Cic. Tusc. 1, 5, 10; id. N. D. 3, 17, 43; Verg. G. 3, 38; 4, 479; id. A. 6, 132; 6, 297; 6, 323; Hor. C. 2, 14, 18 al.; acc. Gr. Cocyton, Claud. Rapt. Pros. 2, 353; cf. Heyne, Verg. A. 6 Excurs. IX.
  2. II. Adj.: Cōcȳtĭus, a, um, of Cocytus: aqua, Petr. 120, 69; and Cocytia aequora, Claud. in Rufin. 2, 471: virgo, i. e. Alecto, Verg. A. 7, 479.