asteroid belt

Short definition from Wiktionary

Proper noun

1. 1
   The main asteroid belt, the region of the orbital plane of the Solar System located between the orbits of Mars and Jupiter which is occupied by numerous minor planets (asteroids) and the dwarf planet Ceres.
2. 2
   Alternative letter-case form of asteroid belt.

Noun

1. 1
   A set of orbits in a region that contains asteroids or similar minor planets arrayed as an annulus around the planetary system's orbital center.