Asteroid - Definitions from Dictionary.com

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Dictionary.com Unabridged (v 1.1) - Cite This Source - Share This

as·ter·oid

Audio Help [as-tuh-roid] Pronunciation Key

–noun

1.	Also called minor planet. Astronomy. any of the thousands of small bodies of from 480 miles (775 km) to less than one mile (1.6 km) in diameter that revolve about the sun in orbits lying mostly between those of Mars and Jupiter.

2.	Zoology. an asteroidean; a starfish.

–adjective

starlike.

[Origin: 1795–1805; < Gk asteroeids starry, starlike. See asterisk, -oid

]

—Related forms

as·ter·oi·dal, adjective

Dictionary.com Unabridged (v 1.1)
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2006.

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Asteroid

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American Heritage Dictionary - Cite This Source - Share This

as·ter·oid Audio Help (ās'tə-roid') Pronunciation Key
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.
Zoology See starfish.

adj. also as·ter·oi·dal (ās'tə-roid'l)
Star-shaped.

[From Greek asteroeidēs, starlike : astēr, star; see ster-³ in Indo-European roots + -oeidēs, -oid.]

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The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2006 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.

American Heritage Dictionary - Cite This Source - Share This

star·fish Audio Help (stär'fĭsh') Pronunciation Key
n. pl. starfish or star·fish·es
Any of various marine echinoderms of the class Asteroidea, characteristically having a thick, often spiny body with five arms extending from a central disk. Also called asteroid, sea star.

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The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2006 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.

Online Etymology Dictionary - Cite This Source - Share This
asteroid

1802, coined by Herschel from Gk. asteroeides "star-like," from aster "star" (see star) + -eidos "form, shape" (see -oid).

WordNet - Cite This Source - Share This

asteroid
adjective
1.	shaped like a star
noun
1.	any of numerous small celestial bodies composed of rock and metal that move around the sun (mainly between the orbits of Mars and Jupiter)

The American Heritage Science Dictionary - Cite This Source - Share This

asteroid Audio Help (ās'tə-roid') Pronunciation Key
Any of numerous small, often irregularly shaped rocky bodies that orbit the Sun primarily in the asteroid belt, a region between the orbits of Mars and Jupiter. Asteroids are intermediate in size between planets and meteoroids; the largest asteroid in the asteroid belt is Ceres, approximately 1,000 km (620 mi) in diameter, while the lower limit is variously given in the tens or hundreds of meters. While more than 1,800 asteroids have been cataloged, and as many as a million or more smaller ones may exist, their total mass has been estimated to be less than three percent of the Moon's. Asteroids are thought to be left over from the early formation of the solar system, when planetesimals in a protoplanetary disk were scattered after coming under Jupiter's gravitational influence. The continuing collision of planetesimals that remained between Jupiter and Mars caused many of them to fragment, creating the asteroids that exist today. Also called minor planet, planetoid.

The American Heritage® Science Dictionary
Copyright © 2002 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.

American Heritage New Dictionary of Cultural Literacy, Third Edition - Cite This Source - Share This
asteroid [(as-tuh-royd)]

A small planet that revolves around the sun. The largest asteroid is only about six hundred miles in diameter. (See asteroid belt.)

[Chapter:] Physical Sciences and Mathematics

Webster's Revised Unabridged Dictionary - Cite This Source - Share This

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.

Acronym Finder - Cite This Source - Share This

ASTEROID

ASTEROID: in Acronym Finder

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