What is a group of Asteroids called?

A group of asteroids is commonly called a Belt. Other collective nouns you may see include Cluster and Stream.

A collective noun for asteroids is an "swarm." When observing the vast expanses of outer space, we can find numerous asteroids scattered throughout the celestial realm. These rocky and metallic objects, remnants from the formation of our solar system, frequently gather in groups known as swarms. Like a collection of buzzing bees, these swarms of asteroids navigate the gravitational forces that thread the cosmos, forming captivating clusters that traverse the interplanetary expanse. The term "swarm" captures the essence of how these asteroids congregate, not merely drifting individually but appearing in bundles or shoals. While each asteroid holds its unique composition, ranging from spherical rocks to elongated shapes, their shared proximity and gravitational bonds evoke an image of a harmonious swarm, navigating in cosmic unison. The collective noun "swarm" communicates their dynamic nature and multi-faceted characteristics. These swarms fulfill astronomical phenomena that dot our solar system, continuously in motion, and humbling our understanding of space. Occasionally, these gatherings of asteroids might temporally unite and form stunning flyby displays, streaking across our skies, reinvigorating our imagination with the grandeur of the universe. In conclusion, the collective noun "swarm" aptly describes the captivating clusters of asteroids in space. Each cohesive gathering existing as a testament to the enigmatic wonders of our celestial neighborhood and perpetually reminding us of the infinite possibilities that lie beyond the confines of our own atmosphere.