(the Greater Dog; abbrev. CMa, gen. Canis Majoris; area 380 sq. deg.) A southern constellation which lies between Lepus and Puppis, and culminates at midnight in early January. It represents one of the two dogs of Orion (the Hunter), which dominates the sky to the north-west (the other dog being represented by Canis Minor). Its brightest star, α Canis Majoris (Sirius), is known as the `dog star'.