The Collaborative International Dictionary of English v.0.48:

Sirius \Sir"i*us\, n. [L., fr. Gr. ???, properly, scorching.]
   (Astron.)
   The Dog Star. See Dog Star.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Sirius
    n 1: the brightest star in the sky; in Canis Major [syn:
         Sirius, Dog Star, Canicula, Sothis]