A constellation is a group of stars, usually in a recognizable shape or pattern. Together, the stars look like a picture. The word constellation comes from Latin: con-, meaning together and stella- meaning stars. Some examples of constellations are Ursa Major, Orion, and Andromeda. There are only 88 constellations discovered so far by astronomers. People used constellations to tell the difference in the colors. Constellations were also used to group stars. Different places in the world may have different constellations, but today astronomy has a fixed set of 88 constellations. This set is based on the Greek set and later some southern constellations were added, for example Antlia - the airpump. Most constellations have names that come from Greek mythology, like Orion or Andromeda.
There are 12 constellations in the Zodiac. The Sun travels through the Zodiac once each year. There is also a thirteenth constellation Ophiuchus - the carrier of a serpent, which the Sun goes through. However, most people do not think that it is in the Zodiac.