brightest star in the northern constellation Canis Minor (Lesser Dog) and one of the brightest in the entire sky, with an apparent visual magnitude of 0.41. Procyon lies about 11 light-years from the Earth and is a visual binary, a bright yellow-white subgiant with a faint, white dwarf companion of about the 10th magnitude. The name apparently derives from Greek words for “before the dog,” in reference to the constellation.