Astronomy Answers
From the Astronomical Dictionary

The description of the word you requested from the astronomical dictionary is given below.

the constellation ⇒

con- = [Latin] together, with; stella = [Latin] star

A constellation is

1. a group of stars that form a pattern that made someone think of a certain person, animal, or object, which makes the pattern easier to remember and find again.
2. an area of the sky, designated by the International Astronomical Union (IAU), in which there is a group of stars that form a pattern as described above. The area of the sky has the same name as the group of stars.

Professional astronomical publications throughout the world always use the constellations as defined by the IAU, but in the past many other constellations were proposed, and in different areas of the world completely different sets of constellations were (and are still) used.