Definition of asteroid in English:



  • 1A small rocky body orbiting the sun. Large numbers of these, ranging enormously in size, are found between the orbits of Mars and Jupiter, though some have more eccentric orbits.

    • ‘In our own solar system, asteroids have collided with Earth, the moon and other planets.’
    • ‘Comets and asteroids also contribute to the near-Earth space environment.’
    • ‘Dinosaurs may not have been killed off by asteroid impact dust blocking out sunlight, a geologist says.’
    • ‘You can also get asteroid hazard warnings and geomagnetic storm outlooks.’
    • ‘Some explanations for extinctions and evolution include strikes by asteroids or comets.’
    • ‘When the asteroid hit, it was vaporized by the extreme energy of the impact.’
    • ‘Both comets and asteroids are the left-over building blocks of the planets in our solar system.’
    • ‘These scientists also study the natural satellites of other planets as well as asteroids and comets.’
    • ‘It's just that you can't keep quiet about things like asteroid impacts.’
    • ‘Our star system is chock full of asteroids and comets, in every conceivable orbit and location.’
    • ‘We know very little about these families of asteroids following the same orbit.’
    • ‘Our knowledge of comets and asteroids has dramatically improved over the last 20 years.’
    • ‘Most of the known asteroids orbit the sun in a belt between Mars and Jupiter.’
    • ‘In many ways asteroids and comets are likely to offer more varied and abundant natural resources than the Moon.’
    • ‘Ceres was initially considered to be a planet until other asteroids with similar orbits were found.’
    • ‘It has been suggested that impacts with comets and asteroids provided Earth with much of its water.’
    • ‘Most of the larger asteroids and comets are also in stable orbits around the sun.’
    • ‘There may be other families of small asteroids within our solar system that, even now, remain to be discovered.’
    • ‘These glaciers are spotted with craters caused by asteroid impacts.’
    • ‘Amateur astronomers have made many asteroid, comet, and supernova discoveries.’
    • ‘Fragments of asteroids and comets pervade interplanetary space.’
    • ‘Once an asteroid drifts into either of those regions, it's hard for it to get out.’
    • ‘So to neglect the problem means that we are vulnerable to asteroid collisions.’
    celestial body, heavenly body, sun
    View synonyms
  • 2Zoology
    An echinoderm of the class Asteroidea, which comprises the starfishes.

    • ‘Available morphological data suggest no ecologic parameters that would be unusual among living asteroids.’
    • ‘The fossil record is a potential source of needed data, although fossil asteroids are rare, and they tend to be poorly preserved.’
    • ‘The asteroid is preserved with the dorsal surface exposed.’
    • ‘An unpaired commonly enlarged interbrachial ossicle, the axillary, occurs in most Paleozoic asteroids, including those treated here.’
    • ‘Both approaches will shed light on the adaptive significance and functional morphology of asteroids.’


  • Relating to or denoting echinoderms of the class Asteroidea.


Early 19th century: from Greek asteroeidēs starlike, from astēr star.