from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. Astronomy Any of numerous small celestial bodies that revolve around the sun, with orbits lying chiefly between Mars and Jupiter and characteristic diameters between a few and several hundred kilometers. Also called minor planet, planetoid.
  • n. Zoology See starfish.
  • adj. Star-shaped.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. A naturally occurring solid object, which is smaller than a planet and is not a comet, that orbits a star
  • n. In the Solar system, such a body that orbits within the orbit of Jupiter
  • n. Any member of the taxonomic class Asteroidea; a starfish

from the GNU version of the Collaborative International Dictionary of English

  • n. 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.

from The Century Dictionary and Cyclopedia

  • Star-like.
  • Having a flower like that of an aster.
  • n. One of the small planets, 280 or more in number, between the orbits of Mars and Jupiter: more accurately called planetoids. See planetoid.
  • n. One of the Asteroidea; a starfish, in a wide sense.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • adj. shaped like a star
  • 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)


From Greek asteroeidēs, starlike : astēr, star; see ster-3 in Indo-European roots + -oeidēs, -oid.
(American Heritage® Dictionary of the English Language, Fourth Edition)
From Ancient Greek ἀστεροειδής, from Ancient Greek ἀστήρ (astēr, "star") + εἶδος (eidos, "form"). (Wiktionary)



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  • 1819, people are hating on the word asteroid

    "But all this is, in our opinion, very unnecessary, while it is indicative of a jealousy with regard to fame, unworthy of him who has discovered whole words.  And, after all, the new term is by no means appropriate.  An asteroid is, from its derivation, "a body resembling fixed stars:" newly-found heavenly bodies have no one circumstance in common with those luminaries. "

    July 17, 2015