noun

asteroid

/ˈæstərɔɪd/ · say it: AS·ter·oid

a small rocky body orbiting the sun

In Science & Nature

In more detail

1. (noun) a small rocky object that moves around the sun, similar to a planet but much smaller

2. (noun) in astronomy, any of thousands of small rocky bodies that orbit between Mars and Jupiter

Examples

1. Scientists discovered a new asteroid near Earth.
2. The asteroid belt contains millions of small objects.

How to use asteroid

Asteroid is a technical term used in astronomy to refer to rocky bodies orbiting the sun, smaller than planets but distinguished from comets by their lack of a visible tail. It is commonly used in scientific contexts, popular science writing, and discussions of space exploration or planetary science. The term is more precise than the informal 'space rock.'

Common phrases

asteroid belt
near-Earth asteroid
asteroid impact
asteroid collision
detect an asteroid
asteroid mining

Synonyms

space rock · minor planet · celestial body · planetoid

Word family

asteroidal (adjective)

A common mistake

Learners sometimes confuse asteroids with meteorites, but meteorites are fragments that have already fallen to Earth, whereas asteroids are objects still in space.

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