The Collaborative International Dictionary of English v.0.48:

Meteoroid \Me"te*or*oid\ (m[=e]"t[-e]*[~e]r*oid), n. [Meteor +
   -oid.] (Astron.)
   A small body moving through space, or revolving about the
   sun, which on entering the earth's atmosphere would be
   deflagrated and appear as a meteor.
   [1913 Webster]

         These bodies [small, solid bodies] before they come
         into the air, I call meteoroids.         --H. A.
                                                  Newton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

meteoroid
    n 1: (astronomy) any of the small solid extraterrestrial bodies
         that hits the earth's atmosphere [syn: meteoroid,
         meteor]