Question

Group of stars that form a pattern

Answer 1

Hint Group of stars you see in the night sky form certain patterns
And each pattern has its own name like Orion, Scorpius, Lyra etc. Now all patterns collectively have a name which is what the question is about.

Complete Step by Step Answer The patterns of stars in the sky are called Constellations but to be more accurate, a group of stars that form a pattern in the sky is called Asterism but generally the term Constellation is used. A Constellation is a group of visible stars which form a pattern or perceived outline representing various things according to some mythologies like an animal or person or an object. Officially there are 88 constellations with boundaries. Constellations in the Northern Hemisphere are invented by ancient Greeks while those in the Southern Hemisphere are based on European Explorers. Some examples are Hydra, Ursa Major, Ursa Minor, Aquila etc.
There are billions of stars in the sky but all the stars are not called constellations. Only those stars that can be perceived as some patterns are constellations. Ancient sky observers loved associating stars with pictures and patterns and that's why we have names for a cluster of stars. Astronomers use these constellations to locate artificial satellites and also are used to find directions. In Fact all of astronomy is based on stars and planets.

Note
There are 12 zodiac signs we have like Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpius etc are called major constellations. It is observed that constellations shift gradually towards the west the whole year.