asteroid

Short definition from Wiktionary

Noun

1. 1
   A naturally occurring solid object, which is smaller than a planet and a dwarf planet, larger than a meteoroid and not a comet, that orbits a star and often has an irregular shape.
2. 2
   In the Solar system, such a body that orbits within the orbit of Jupiter
3. 3
   Any member of the taxonomic class Asteroidea; a starfish.