Lewis & Short

Cerbĕrus (-ros), i, m., = Κέρβερος,

  1. I. the three- (acc. to others, the hundred-) headed monster Cerberus, Lucr. 3, 10; 3, 24; Verg. G. 4, 483; id. A. 6, 417; Prop. 3 (4), 5, 44; Hor. C. 2, 19, 29; 3, 11, 17; Ov. M. 4, 450; Hyg. Fab. 151 (cf. Verg. A. 6, 400; Hor. C. 2, 13, 34); Cic. Tusc. 1, 5, 10 al.
    Hence,
  2. II. Cerbĕrĕus, a, um, adj., of or pertaining to Cerberus: facies canum, Lucr. 4, 735: os, Ov. M. 4, 501: latratus, Stat. S. 5, 1, 249: portae, i. e. of the Lower World, id. Th. 8, 56.