asteroid

[as-tuh-roid]

noun

1. Astronomy.,  any of millions of small celestial objects revolving around the sun, often irregularly shaped and having a great range in size, from as small as 6 feet (2 meters) across to about 620 miles (998 kilometers) across: the vast majority of known asteroids exist within the asteroid belt.

2. Zoology.,  a starfish; an asteroidean.

adjective

1. starlike.

asteroid

/ ˈæstəˌrɔɪd /

noun

1. 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. Also called: asteroidean. any echinoderm of the class Asteroidea; a starfish

adjective

1. of, relating to, or belonging to the class Asteroidea

2. shaped like a star

asteroid

1. 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.

2. Also called minor planet planetoid

asteroid

1. A small planet that revolves around the sun. The largest asteroid is only about six hundred miles in diameter. (See asteroid belt.)

Other Word Forms

• asteroidal adjective
• interasteroidal adjective

Word History and Origins

Origin of asteroid¹

First recorded in 1795–1805; from Greek asteroeidḗs “starry, starlike”; star, -oid

Word History and Origins

Origin of asteroid¹

C19: from Greek asteroeidēs starlike, from astēr a star

Example Sentences

Experts also took issue with the ranking’s focus on the states with the highest chances of spotting an asteroid, since you can’t actually see an asteroid with the naked eye from anywhere.

From Los Angeles Times

Meteor showers occur when Earth passes through trails of dust and debris left behind by comets or asteroids.

From BBC

Harris is hoping to publish his findings on the composition and speed of the asteroid, which will help to understand the threat of further asteroids.

From BBC

Meteorites are the remains of rock left after an asteroid or comet passes through Earth's atmosphere.

From BBC

A random asteroid wiping out her kingdom soon after she accepts Dream’s marriage proposal only proves her point.

From Salon

Related Words

• earth 
• globe 
• sphere 
• world