Lewis & Short

Constantīnus, i, m., C. Flavius Vaferius Claudius Constantinus, Constantine, a well-known Roman emperor, born A. D. 274, died A. D. 323, Eutr. 10, 2 sqq.; Lact. Mort. Pers. 18 sqq.; Amm. 21, 10, 8.
Hence, Constantīnĭānus, a, um, adj., of or pertaining to Constantine: genus, Amm. 27, 5, 1: lavacrum, id. 27, 3, 8.