Lewis & Short

Chăŏs or Chăus, abl. Chao (other cases not used in the class. per.; gen. Chaï, Serv. ad Verg. A. 1, 664; dat. Chaï, Prisc. p. 720 P.), n., = Χάος.

  1. I. The boundless, empty space; as the kingdom of darkness, the Lower World: ingens, Ov. M. 10, 30; 14, 404; id. Ib. 84: inane, id. F. 4, 600: caecum, Sen. Med. 741; Stat. Th. 12, 772; Val. Fl. 7, 402; impersonated, masc., god of the Lower World, father of Erebos and Nox, Verg. A. 4, 510 (acc. Chaos); 6, 265; Quint. 3, 7, 8; cf.: Janus … edidit hos sonos; me Chaos antiqui, nam sum res prisca, vocabant, Ov. F. 1, 103.
    1. B. Hence also, immeasurable darkness, deep obscurity: Cimmerium, Stat. S. 3, 2, 92: horridum, Prud. Cath. 5, 3.
  2. II. The confused, formless, primitive mass out of which the universe was made, chaos, Ov. M. 1, 7; 2, 299; Lact. 1, 5, 8; 2, 8, 8: a Chao, since the creation of the world, Verg. G. 4, 347.