Definition from Wiktionary, the free dictionary
From the fact that the star lies in the constellation of Canis Major (the "larger dog")
- (astronomy) A bluish-white star in the constellation Canis Major; Alpha (α) Canis Majoris. A vertex of the Winter Triangle and the brightest star in the night sky. It is actually a binary star with a white dwarf companion star.
Sirius — see Sirius