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. small solar system body.
2. Zoology. a starfish; an asteroidean.

adjective

1. starlike.

asteroid

/ ˈæstəˌrɔɪd /

noun

1. Also calledminor planetplanetoid 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 calledasteroideanˌæstəˈrɔɪdɪən 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

/ ăs′tə-roid′ /

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 Words From

• as·ter·oi·dal adjective
• in·ter·as·ter·oi·dal 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

Steve Schmidt, a former Republican political consultant and Trump opponent, described the comment as a potential “killer asteroid” moment for the Harris campaign.

From Los Angeles Times

The team also found evidence that massive asteroid impacts did not bring only destruction to Earth - they helped early life thrive.

From BBC

Long after the GOBE, about 66 million years ago, when ecosystems on land were as full of varied living things as the seas, a 6-mile-wide asteroid struck Earth at a place we now call Chicxulub, on the Yucatán Peninsula.

From Slate

Just this year, planetary scientists identified the asteroid as a carbonaceous chondrite, an iron-heavy chunk of rock left over from our solar system’s formation that was pulled onto a collision course with Earth in the most catastrophic million-to-one shot of all time.

From Slate

Without that asteroid, we wouldn’t be here or recognize the planet we now call home.

From Slate

Related Words

• earth
• globe
• sphere
• world