Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Argo, ūs, f. (gen. Argūs, Prop. 3, 22, 19; acc. Argo, Varr. ap. Charis. p. 94 P.; Argon, Prop 1, 20, 17 Müll.; dat. and abl. prob. not used), = Ἀργώ, the name of the ship in which the Greek heroes, under the guidance of Jason, sailed to Colchis in quest of the golden fleece, Enn. ap. Auct. ad Her. 2, 22 (Trag. v. 284 Vahl.); Verg. E. 4. 34 al. Later placed by Minerva as a constellation in heaven (cf. Hyg. Fab. 14), Cic. Arat. 126; also id. N. D. 2, 44, 114, Col. 11, 2, 66: decimo Cal. Octobr. Argo navis occidit: tempestatem significat, interdum pluviam, id. 11, 2, 24.
Acc. to the first signif., Argō-us, a, um, adj., = Ἀργῶος, pertaining to the Argo, and in gen. to the Argonauts, Prop. 4, 22, 13; Hor. Epod. 16, 57; Val. Fl. 5, 436; 6, 116; 7, 573; 8, 294.