as·ter·oid ( s t -roid )n. 1. 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. 2. Zoology See starfish. adj. also as·ter·oi·dal ( st-roidl) Star-shaped. [From Greek asteroeid  s, starlike : astr, star; see ster-3 in Indo-European roots + -oeids, -oid.] |
asteroid [ˈæstəˌrɔɪd]
n
1. (Astronomy & Space / Celestial Objects) 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
2. (Life Sciences & Allied Applications / Zoology) Also called asteroidean [ˌæstəˈrɔɪdɪən] any echinoderm of the class Asteroidea; a starfish
adj also asteroidal [ˌæstəˈrɔɪdəl]
1. (Life Sciences & Allied Applications / Zoology) of, relating to, or belonging to the class Asteroidea
2. shaped like a star
[from Greek asteroeidēs starlike, from astēr a star]
| asteroid (st-roid) 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. |
ThesaurusLegend: Synonyms Related Words Antonyms
| Noun | 1. | asteroid - any of numerous small celestial bodies composed of rock and metal that move around the sun (mainly between the orbits of Mars and Jupiter) Chiron - an asteroid discovered in 1977; it is unique in having an orbit lying mainly between the orbits of Saturn and Uranus minor planet, planetoid - any of numerous small celestial bodies that move around the sun |
| Adj. | 1. | asteroid - shaped like a star |
asteroid
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