noun.
A solid body, moving in space, that is smaller than an asteroid and at least as large as a speck of dust.
The Century Dictionary and Cyclopedia
noun.
A body traveling in space, and of the same nature as those which on entering the earth's atmosphere become visible as meteors.
the GNU version of the Collaborative International Dictionary of English
noun.
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.