The headword phrase is evidently prompted by Homer, where its adjective is a epithet of both cattle (e.g. Iliad 8.231: web address 1) and of ships (Iliad 18.3: web address 2); see Edwards, p. 142. In Homer, only the genitive plural form of the lemma's adjective occurs: o)rqokraira/wn. The nautical sense is uncertain. LSJ s.v. o)rqo/krairos suggests that it refers to the upturned prows and sterns of galleys, which thus resemble cattle horns. In particular, it might allude to an ornamental structure on the stern (Cunliffe s.v., p. 298). The Suda's gloss is an alternative interpretation; see next note. For the lemma, Adler also cites Lexicon Ambrosianum 475 as identical.
[1] The gloss follows the scholion (= D scholia) to Homer, Iliad 18.3 (see above). The sense is thus that the vessel is rigged for sailing directly downwind, with its horizontal spars perpendicular to the ship's centerline.