Lewis & Short

Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.

Būthrōtum, i, n. (Būthrōtŏs, i, f., Ov. M. 13, 721), = Βουθρωτόν and Βουθρωτός, a town on the coast of Epirus, now Butrinto, Caes. B. C. 3, 16; Verg. A. 3, 293 sq.; Mel. 2, 3, 10; Plin. 4, 1, 1, § 4.
Hence, Būthrōtĭus, a, um, adj., of Buthrotum: ager, causa, Cic. Att. 16, 16, A, 4: Plancus, id. ib. 15, 29, 3; and subst.: Būthrōtĭi, ōrum, m., the inhabitants of Buthrotum, id. ib. 14, 11, 2; 15, 2, 2; 16, 16, A, 4.