CYNOSURA, in Astronomy, a denomination given by the Greeks to ursa minor, the little bear, by which sailors steer their course. The word is formed of κύνησα, the dog's tail. This is the constellation next our pole, and consists of seven stars; of which four are disposed like the four wheels of a chariot, and three lengthwise representing the beam; whence some give it the name of a chariot, or Charles's vein.