What term describes a group of stars that forms a shape or pattern?

The term that describes a group of stars forming a specific shape or pattern is "constellations." Constellations have been used since ancient times for navigation, storytelling, and marking the changing seasons. Each constellation is made up of stars that may not be physically related in terms of distance from Earth; they simply appear grouped together in the night sky from our viewpoint.

Galaxies, while they do consist of vast collections of stars, gas, dust, and dark matter, refer to much larger structures that can include billions of stars, whereas constellations are localized groupings as viewed from Earth. Pulsars are specific types of neutron stars that emit beams of radiation, and quasars are incredibly bright objects powered by black holes at the centers of distant galaxies. Thus, the definition of constellations specifically captures the idea of recognizable groupings of stars that form patterns in the night sky.