asteroid
[ as-tuh-roid ]
/ ˈæs təˌrɔɪd /
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noun
Astronomy. any of millions of small celestial objects revolving around the sun, often irregularly shaped and having a great range in size, from as small as 6 feet (2 meters) across to about 620 miles (998 kilometers) across: the vast majority of known asteroids exist within the asteroid belt. See also small solar system body.
Zoology. a starfish; an asteroidean.
adjective
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Origin of asteroid
OTHER WORDS FROM asteroid
as·ter·oi·dal, adjectivein·ter·as·ter·oi·dal, adjectiveWords nearby asteroid
asterism, asterixis, astern, asternal, asternia, asteroid, asteroid belt, asteroid body, Asteroidea, asteroidean, asteroid hyalosis
Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021
Example sentences from the Web for asteroid
British Dictionary definitions for asteroid
asteroid
/ (ˈæstəˌrɔɪd) /
noun
Also called: minor planet, planetoid any of numerous small celestial bodies that move around the sun mainly between the orbits of Mars and Jupiter. Their diameters range from 930 kilometres (Ceres) to less than one kilometre
Also called: asteroidean (ˌæstəˈrɔɪdɪən) any echinoderm of the class Asteroidea; a starfish
adjective Also: asteroidal (ˌæstəˈrɔɪdəl)
of, relating to, or belonging to the class Asteroidea
shaped like a star
Word Origin for asteroid
C19: from Greek asteroeidēs starlike, from astēr a star
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
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Scientific definitions for asteroid
asteroid
[ ăs′tə-roid′ ]
Any of numerous small solar system 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 with diameters that measure between approximately one hundred and several hundred kilometers. 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 © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Cultural definitions for asteroid
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.)
The New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.