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

In 1950, Dutch astronomer Jan Oort—after whom the cloud was ultimately named—suggested the existence of the Oort Cloud to explain from where long-period comets come from. —Dan Perry, Newsweek, 28 Feb. 2025

The spiral is composed of billions of icy bodies surrounded by a shell of comets called the Oort cloud. —Robert Lea, Space.com, 27 Feb. 2025

Now set to launch no earlier than 2027, the telescope is designed to discover 90% of asteroids and comets that are 460 feet in size or larger and come within 30 million miles of Earth’s orbit. —Eric Lagatta, USA TODAY, 26 Feb. 2025

Multiple theories have been raised, from comet impacts to solar wind interacting with the moon to produce hydrogen atoms that combine with existing oxygen atoms under the lunar surface. —Jack Knudson, Discover Magazine, 26 Feb. 2025

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