What do we call a group of stars that form a particular pattern in the sky?

A group of stars that form a particular pattern in the sky is known as a constellation. This term comes from the practice of ancient astronomers who identified specific patterns or shapes in the arrangement of stars, associating them with mythological figures, animals, or objects. Constellations help astronomers navigate the night sky and serve as a reference for locating other celestial bodies.

Galaxies, on the other hand, are vast collections that contain billions of stars, along with gas and dust, and are held together by gravity. While a galaxy can contain many constellations within it, it refers to a much larger structure in the universe.

A star cluster refers to a specific group of stars that are physically close together in space and have a common origin, but do not necessarily form recognizable patterns from Earth's perspective.

A solar system consists of a star and the celestial bodies bound to it by gravity, including planets, moons, asteroids, and comets, which is different from the concept of a constellation entirely.

Thus, the term "constellation" is the correct one for a specific arrangement of stars as observed from Earth.