noun \ˈas-tə-ˌrid\

: any one of thousands of small planets that circle around the sun

Full Definition of ASTEROID

:  any of the small rocky celestial bodies found especially between the orbits of Mars and Jupiter
:  starfish
as·ter·oi·dal \ˌas-tə-ˈri-dəl\ adjective

Examples of ASTEROID

  1. Most asteroids are found between Mars and Jupiter.

Origin of ASTEROID

Greek asteroeidēs starlike, from aster-, astēr
First Known Use: 1802

Other Astronomy Terms

gibbous, nadir, nebulous, penumbra, retrograde, sidereal, syzygy, wane, wax, zenith



Definition of ASTEROID

:  resembling a star <asteroid bodies in sporotrichosis>
:  of or resembling a starfish

First Known Use of ASTEROID



adjective \ˈas-tə-ˌrid\   (Medical Dictionary)

Medical Definition of ASTEROID

: resembling a star


noun    (Concise Encyclopedia)

Any of the many rocky small bodies that orbit the Sun mainly in a flat ring, the asteroid belt, between the orbits of Mars and Jupiter. It is thought that the gravitational influence of what became Jupiter kept the asteroids from aggregating into a single planet while the solar system was forming. Also called minor planets, asteroids are smaller than any of the solar system's major planets; only about 30 are more than 125 mi (200 km) across. Ceres is the largest known asteroid. Millions of boulder-sized asteroidal fragments are thought to exist in the solar system. Asteroids or their fragments regularly strike Earth, plunging through the atmosphere as meteors to reach its surface (see meteorite). Asteroids appear to be composed of carbonaceous, stony, and metallic (mainly iron) materials. See also Earth-crossing asteroid; Trojan asteroids.


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