Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Lū̆cĕres (also Lū̆cĕrenses, or perh. Lūcĕrēses, Paul. ex Fest. p. 119, 10), ium, m., an Etruscan tribe, whose union with the Ramnes (Latins) and Taties (Sabines) gave rise to the oldest Roman state. Romulus named after them one of his three centuries of horsemen: Luceres, ut Junius, a Lucumone, Varr. L. L. 5, §§ 55 and 81 Müll.; Cic. Rep. 2, 8, 14; 2, 20, 36; Liv. 1, 13, 8; 1, 36, 2; Prop. 4 (5), 1, 31; Ov. F. 3, 131: hinc Taties Ramnesque viri Lŭceresque coloni, Prop. 4 (5), 1, 31.