Source : Webster's Revised Unabridged Dictionary (1913)

Asteroid \As"ter*oid\, n. [Gr. ? starlike, starry; 'asth`r star
   + ? form: cf. F. ast['e]ro["i]de. See {Aster}.]
   A starlike body; esp. one of the numerous small planets whose
   orbits lie between those of Mars and Jupiter; -- called also
   {planetoids} and {minor planets}.

Source : WordNet®

asteroid
     adj : shaped like a star [syn: {star-shaped}]

asteroid
     n : any of numerous small celestial bodies composed of rock and
         metal that move around the sun (mainly between the orbits
         of Mars and Jupiter) [syn: {minor planet}, {planetoid}]