Source : Webster's Revised Unabridged Dictionary (1913)

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.

Source : WordNet®

Argo
     n : formerly a large constellation in the southern hemisphere
         between Canis Major and the Southern Cross; now divided
         into Carina and Pyxis and Puppis and Vela