Definitions

from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun 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.

from The Century Dictionary.

  • noun One of a class of celestial bodies which move about the sun in greatly elongated orbits, usually elliptical or parabolic.
  • noun In heraldry, same as blazing-star.
  • noun One of a group of humming-birds with long forked tails: as, the Sappho comet, Cometes sappho; the Phaon comet, Cometes phaon.
  • noun A game of cards, somewhat like speculation, invented and popular in the reign of Louis XV. of France.
  • noun In photography, a comet-shaped defect appearing on gelatin dry plates.

from the GNU version of the Collaborative International Dictionary of English.

  • noun (Astron.) A member of the solar system which usually moves in an elongated orbit, approaching very near to the sun in its perihelion, and receding to a very great distance from it at its aphelion. A comet commonly consists of three parts: the nucleus, the envelope, or coma, and the tail; but one or more of these parts is frequently wanting. See Illustration in Appendix.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun astronomy A celestial body consisting mainly of ice, dust and gas in a (usually very eccentric) orbit around the Sun and having a "tail" of matter blown back from it by the solar wind as it approaches the Sun.
  • noun A celestial phenomenon with the appearance given by the orbiting celestial body.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun (astronomy) a relatively small extraterrestrial body consisting of a frozen mass that travels around the sun in a highly elliptical orbit

Etymologies

from The American Heritage® Dictionary of the English Language, 4th Edition

[Middle English comete, from Old English comēta, from Late Latin, from Latin comētēs, from Greek komētēs, long-haired (star), comet, from komē, hair.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Old French comete (French: comète), from Latin cometes, from Ancient Greek κομήτης (komētēs, "longhaired"), referring to the tail of a comet, from κόμη (komē, "hair").

Support

Help support Wordnik (and make this page ad-free) by adopting the word comet.

Examples

  • With a little imagination, they might look like the heads of mourning women with long, streaming hair -- and in fact, the word comet comes from the Greek word for "hair."

    Recently Uploaded Slideshows 2008

  • No matter how many times you rewind the clock, the comet is still going to hit.

    Convergence 2008

  • A comet is a relatively small extraterrestrialbody witha nucleus of rock, ice, dust and gases.

    Cosmic Projectiles 2008

  • The tail of a comet is formed directly opposite the comet's path to or from the Sun.

    Is That Legal?: The Universe Is Sometimes A Beautiful Place. 2007

  • The tenuous material surrounding a comet is pushed away from the sun by radiation pressure and solar wind.

    A ‘bizzare star’, an incomplete explanation « Skulls in the Stars 2007

  • "Because these particles have come from inside a comet we know that essentially the particles haven't been heated since they became part of the comet, because the comet is made of ice," he told the BBC News website.

    Dru Blood - I believe in the inherent goodness of all beings: Jan 15, 2006 News & Blog roundup 2006

  • "Because these particles have come from inside a comet we know that essentially the particles haven't been heated since they became part of the comet, because the comet is made of ice," he told the BBC News website.

    Dru Blood - I believe in the inherent goodness of all beings: January 2006 Archives 2006

  • The comet is not going to be terribly bright (in part because it has broken up into numerous fragments instead of being a single, whole comet), about magnitude 4, and has just passed through the bottom part of the constellation Lyra (right past Messier 57, the Ring Nebula; see the picture below).

    Archive 2006-05-01 JDsg 2006

  • The comet is not going to be terribly bright (in part because it has broken up into numerous fragments instead of being a single, whole comet), about magnitude 4, and has just passed through the bottom part of the constellation Lyra (right past Messier 57, the Ring Nebula; see the picture below).

    Comet Schwassmann-Wachmann 3 JDsg 2006

  • Me: That's a smart idea because once the real comet is gone it won't be back for another 4,000 years.

    Curiosity and Comets Jessica 2005

Comments

Log in or sign up to get involved in the conversation. It's quick and easy.

  • As unknown comets from space, so come man's thoughts to his mind; but once they're named we all feel MUCH BETTER. --Jan Cox

    April 6, 2007

  • It makes your mouth all green. ;-)

    July 12, 2007

  • An it's nasty gritty acrid!

    July 12, 2007

  • Comet is a powdered cleaning product sold in North America and distributed in the USA by Prestige Brands. Scratch Free Comet with Bleach Disinfectant Cleanser contains 1.2% sodium dichloro-s-triazinetrione dihydrate and 98.8% "other" ingredients. The only clues about the other ingredients in the product are disclaimers on the label that mention that the surfactants in the product are biodegradable and that it contains no phosphate. Despite being labeled as scratch free, its label instructs to use plenty of water on delicate surfaces. Comet is not recommended for use on silver, painted surfaces, walls, soft plastic, aluminum, or rubber, except for tires. Mixing Comet with other cleaners, specifically toilet bowl cleaners and products that contain ammonia, is dangerous.

    _Wikipedia

    February 1, 2008