asteroid

noun as·ter·oid \ ˈas-tə-ˌrȯid \

|Updated on: 6 Aug 2018

Examples: asteroid in a Sentence

Definition of asteroid

1 : any of the small rocky celestial bodies found especially between the orbits of Mars and Jupiter

2 : starfish

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asteroidal

play \ˌas-tə-ˈrȯi-dᵊl\ adjective

See asteroid defined for English-language learners

See asteroid defined for kids

Examples of asteroid in a Sentence

Most asteroids are found between Mars and Jupiter.

Recent Examples of asteroid from the Web

The cigar-shape space rock was thought to be a comet, but it was reclassified as an asteroid after astronomers failed to detect telltale gas emissions.

— matt warren, Science | AAAS, "Mysterious interstellar visitor is a comet, flight path reveals," 27 June 2018
Equal parts science-fiction adventure and political thriller, this series opened with a plot set for disaster: An M.I.T. grad student (Charlie Rowe) and a tech genius (Santiago Cabrera) discover an asteroid will collide with Earth in six months.

— sara aridi, New York Times, "What’s on TV Monday: ‘Salvation’ and ‘Ballet 422’," 25 June 2018
According to the action plan, implementing these five goals should improve the U.S. preparedness for NEO impact within the next 10 years — if an asteroid doesn’t get us first.

— john patrick pullen, Fortune, "Here's How NASA Plans to Protect Earth From Giant Asteroids Hurtling Through Space," 21 June 2018
An asteroid the size of the Statue of Liberty will zoom past Earth on Tuesday.

— alix langone, Time, "An Asteroid the Size of the Statue of Liberty Will Whiz Past Earth Tomorrow. Here's How to See It," 14 May 2018
Yet with no interim revenue ahead of reaching the asteroids, Planetary burned through its money.

— dominic gates, The Seattle Times, "While some NW space companies show progress, asteroid miner Planetary Resources is in rocky shape," 26 June 2018
If an asteroid was going to destroy our planet, now would be the time to just get it over with.

— matt simon, WIRED, "Can a New Kind of Consumerism Help Fight Climate Change?," 4 June 2018
Keen observers will also have the rare opportunity to witness the brightest asteroid in the solar system become visible to the naked eye.

— National Geographic, "Naked-Eye Asteroid and More Can't-Miss Sky Events in June," 1 June 2018
They're classified as Hamamiyidans — which thrived before the rise of modern mammals, which took place after the giant asteroid slammed into the earth, killing off most of the dinosaurs 65 million years ago, according to Live Science.

— matthew martinez, sacbee, "Fossilized skull found in Utah belongs to newly discovered half mammal, half reptile," 31 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'asteroid.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of asteroid

Greek asteroeidēs starlike, from aster-, astēr

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First Known Use: 1802

in the meaning defined at sense 1

See Words from the same year

Other Astronomy Terms

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

asteroid

adjective

Definition of asteroid

1 : resembling a star

asteroid bodies in sporotrichosis

2 : of or resembling a starfish

Recent Examples of asteroid from the Web

Launched in 2014, Hayabusa2 is just now approaching its target, Ryugu, an asteroid about half a mile wide.

— kenneth chang, New York Times, "Japan’s Hayabusa2 Spacecraft Creeps Up on the Ryugu Asteroid," 25 June 2018
With a mountain peak in the Arctic and an asteroid zooming through space bearing her name, Marvin leaves a legacy as a geologist of the boundless and as a ceaseless adventurer.

— leila mcneill, Smithsonian, "The Rockstar Geologist Who Mapped the Minerals of the Cosmos," 30 Mar. 2018
Renderings show an astronaut outpost shrouded in lunar soil, which is molded into an exterior shell around the modules to protect them from radiation, asteroid strikes and temperature fluctuations.

— NBC News, "Here's what future Mars and lunar space colonies could look like," 7 July 2018
Hayabusa2 Arrives at Asteroid Ryugu Japan’s Hayabusa2 spacecraft has arrived at Ryugu, an asteroid thought to contain material from the early solar system.

— kenneth chang, New York Times, "Japan’s Hayabusa2 Spacecraft Creeps Up on the Ryugu Asteroid," 25 June 2018
Other impact craters tell a tale similar to that idea: The 85-kilometer Chesapeake Bay crater, for instance, was devoid of life for thousands of years after a comet or asteroid hit modern-day Virginia some 35 million years ago.

— katherine kornei, Science | AAAS, "Life rebounded just years after the dinosaur-killing asteroid struck," 30 May 2018
In 2017, the first observed interstellar visitor, an asteroid named 'Oumuamua, was found traveling through our solar system.

— ashley strickland, CNN, "This object isn't supposed to be in our solar system," 21 May 2018
Geologists and astrophysicists were long aware of craters caused by asteroid strikes, Morrison says.

— Popular Mechanics, "The Asteroid Hunters," 11 Nov. 2015
The missions and asteroid mining of the future aren’t the only things pushing a revamp of planetary protection.

— adam rogers, WIRED, "In Search of New Rules to Protect Other Worlds From Earth's Cooties," 2 July 2018

First Known Use of asteroid

1824

in the meaning defined at sense 1

See Words from the same year

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ASTEROID Defined for English Language Learners

asteroid

noun

Definition of asteroid for English Language Learners

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

ASTEROID Defined for Kids

asteroid

noun as·ter·oid \ ˈa-stə-ˌrȯid \

Definition of asteroid for Students

: one of thousands of rocky objects that move in orbits mostly between those of Mars and Jupiter and have diameters from a fraction of a mile to nearly 500 miles (800 kilometers)