A cluster or group of fixed stars, or division of the heavens, designated in most cases by the name of some animal, or of some mythologial personage, within whose imaginary outline, as traced upon the heavens, the group is included. "The constellations seem to have been almost purposely named and delineated to cause as much confusion and inconvenience as possible." Note: In each of the constellations now recognized by astronomers (about 90 in number) the brightest stars, both named and unnamed, are designated nearly in the order of brilliancy by the letters of the Greek alphabet; as, alpha Tauri (Aldebaran) is the first star of Taurus, gamma Orionis (Bellatrix) is the third star of Orion.