comet

UK: /ˈkɒmɪt/ US: /ˈkɑmɪt/ ,(kom′it)

WordReference Random House Learner's Dictionary of American English © 2025

com•et /ˈkɑmɪt/   n. [countable]

1. Astronomy a body in space made up of a bright, central solid mass and a tail of dust and gas and that orbits the sun:
   Halley's comet.

com•et•ar•y /ˈkɑmɪˌtɛri/  adj. 

WordReference Random House Unabridged Dictionary of American English © 2025

com•et  (kom′it), n. [Astron.]

1. Astronomy a celestial body moving about the sun, usually in a highly eccentric orbit, consisting of a central mass surrounded by an envelope of dust and gas that may form a tail that streams away from the sun.

• Greek komé̄tēs wearing long hair, equivalent. to komē-, variant stem of komân to let one's hair grow (derivative of kómē hair) + -tēs agent suffix
• Latin comētēs, comēta
• Anglo-French, Old French
• 1150–1200; Middle English comete

com•et•ar•y  (kom′i ter′ē), co•met•ic  (kə met′ik), co•met′i•cal, adj.  com′et•like′, adj. 

Collins Concise English Dictionary © HarperCollins Publishers::

comet / ˈkɒmɪt/ noun

1. a celestial body that travels around the sun, usually in a highly elliptical orbit: thought to consist of a solid frozen nucleus part of which vaporizes on approaching the sun to form a gaseous luminous coma and a long luminous tail

Etymology: 13th Century: from Old French comète, from Latin comēta, from Greek komētēs long-haired, from komē hair

ˈcometary, cometic / kɒˈmɛtɪk/ adjective