What is a constellation?

A constellation is a group of stars thought to make a shape in the night sky. Most are not actually close astronomically, but appear that way in the sky. Various groups of stars were historically seen as forming patterns, or outlines, that are identified in astronomy and astrology. There are 88 designated constellations in modern astronomy, and 12 that are recognized as astrological signs because the Sun appears to reside in each for a twelfth of the year.