from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun Astronomy Any of numerous small solar system bodies that revolve around the sun, with orbits lying chiefly between Mars and Jupiter and characteristic diameters roughly between one and several hundred kilometers.
  • adjective Star-shaped.

from The Century Dictionary.

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

from the GNU version of the Collaborative International Dictionary of English.

  • noun 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 Wiktionary, Creative Commons Attribution/Share-Alike License.

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

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

  • adjective shaped like a star
  • noun 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 The American Heritage® Dictionary of the English Language, 4th Edition

[From Greek asteroeidēs, starlike : astēr, star; see ster- in Indo-European roots + -oeidēs, -oid.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Ancient Greek ἀστεροειδής, from Ancient Greek ἀστήρ (astēr, "star") + εἶδος (eidos, "form").


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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