- The definition of a comet is a celestial body that moves around the sun, and as it goes near the sun it forms a vapor trail of dust and gas that streams after it.
An example of comet is Haley's.
The McNaught comet at sunset.
a small, frozen mass of dust and gas revolving around the sun in a parabolic or elliptical orbit: as it nears the sun it vaporizes, forming a coma and, usually, a long tail of ions that points away from the sun
Origin of cometMiddle English comete ; from Old English cometa and amp; Old French comete, both ; from Classical Latin cometa ; from Classical Greek komētēs, literally , long-haired Americanism ; from komē, literally , hair of the head
A celestial body, observed only in that part of its orbit that is relatively close to the sun, having a head consisting of a solid nucleus surrounded by a nebulous coma up to 2.4 million kilometers (1.5 million miles) in diameter and an elongated curved vapor tail arising from the coma when sufficiently close to the sun. Comets are thought to consist chiefly of ammonia, methane, carbon dioxide, and water.
Origin of cometMiddle English comete, from Old English comēta, from Late Latin, from Latin comētēs, from Greek komētēs, long-haired (star), comet, from komē, hair.
- com′et·ar′y , co·met′ic
Comet Hyakutake was discovered by Yuji Hyakutake of Japan on January 30, 1996