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

The bulk of the moon’s water was likely delivered via asteroid and comet impacts about four billion years ago, says David Kring, leader of the Center for Lunar Science & Exploration, who was not involved in the study. —K. R. Callaway, Scientific American, 18 Mar. 2026

The authors of the latest paper also determined that the methanol was emanating from both the comet’s core and coma, yet another intriguing piece of the interstellar puzzle. —Victor Tangermann, Futurism, 11 Mar. 2026

Astronomers studying the interstellar visitor 3I/ATLAS have discovered the comet is unusually rich in alcohol — a chemical clue that could reveal how planets and icy bodies form around other stars. —Samantha Mathewson, Space.com, 11 Mar. 2026

Set to launch no earlier than September 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, 10 Mar. 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