- 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.
- Zoology. an asteroidean; a starfish.
Origin of asteroid
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Related Wordssphere, earth, globe, world, asteroid, marble, orb, apple, planetoid, moon, rocket, spacecraft, luna, sputnik, terrene, ancillary
Examples from the Web for asteroid
What would it take to carry people to the Moon, or Mars, or an asteroid?
Thinking of longer journeys to Mars or an asteroid would require careful measurement of conditions.
His game lasts until his final ship has either collided with an asteroid or lost a shootout with an enemy saucer.‘Asteroids’ & The Dawn of the Gamer Age
November 29, 2014
The Asteroid Belt in the Solar System has many such gaps, created by the gravity of the Sun and Jupiter.The Most Stunning View Ever of Planets Being Born
Matthew R. Francis
November 9, 2014
For the record, Deep Impact is about a comet, not an asteroid.U.S.—Russia Tensions Nuke Plans For Real-Life ‘Armageddon’ Asteroid Defense
August 4, 2014
But the mechanism controlling the asteroid's invisibility was not destroyed.The Bluff of the Hawk
The first was never heard of after thirty-six hours on the asteroid.
Anything that kept them from selling an asteroid must be terrible indeed.
The asteroid was too tiny to give him indefinite concealment.
For an instant there was a silence in the darkness of the asteroid that was painful.
- 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
- of, relating to, or belonging to the class Asteroidea
- shaped like a star
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 Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for asteroid
Online Etymology Dictionary, © 2010 Douglas Harper
- 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
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