Argo \Ar"go\, n. [L. Argo, Gr. ?.] 1. (Myth.) The name of the ship which carried Jason and his fifty-four companions to Colchis, in quest of the Golden Fleece. 2. (Astron.) A large constellation in the southern hemisphere, called also {Argo Navis}. In modern astronomy it is replaced by its three divisions, Carina, Puppis, and Vela.