comet

noun

com·​et ˈkä-mət 

: a celestial body that appears as a fuzzy head usually surrounding a bright nucleus, that has a usually highly eccentric orbit, that consists primarily of ice and dust, and that often develops one or more long tails when near the sun

cometary

ˈkä-mə-ˌter-ē 

adjective

cometic

kə-ˈme-tik 

kä-

adjective

Examples of comet in a Sentence

Recent Examples on the Web

Named McGetchin crater, the feature formed sometime between April 11 and May 22 in the year 2024 when an asteroid or comet fragment struck the moon. — Samantha Mathewson, Space.com, 17 Sep. 2026

Debris from asteroid and comet impacts has obscured evidence of the planet's shrinkage. — Eric Lagatta, USA Today, 11 Sep. 2026

But asteroids and comets have also bombarded Mercury, riddling it with impact craters, much like the pockmarked surface of Earth’s moon. — Ashley Strickland, CNN Money, 10 Sep. 2026

In June, astronomers noted a surface eruption increased the comet’s luminosity by almost 10 magnitudes—making it around 8,000 times brighter than usual. — Andrew Paul, Popular Science, 27 Aug. 2026

Word History

Etymology

Middle English comete, from Old English cometa, from Latin, from Greek komētēs, literally, long-haired, from koman to wear long hair, from komē hair

First Known Use

before the 12th century, in the meaning defined above

Rhymes for comet

• grommet
• vomit
• recommit

Kids Definition

comet

noun

com·​et ˈkäm-ət 

: a bright heavenly body that develops a cloudy tail as it moves closer to the sun in its orbit

Etymology

Old English cometa "comet," from Latin cometa (same meaning), from Greek komētēs, literally, "long-haired," derived from komē "hair" — related to coma entry 2