Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† 1. ōtus, i, m., = ὦτος or ὠτός, a kind of owl, the horned owl, Plin. 10, 23, 33, § 66.
2. Ōtus (also Ōtos, Ōthos, and Oetus), i, m., the name of a giant: immanis Otos, Verg. Cul. 233; cf. Hyg. Fab. 28.