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planet

[plan-it] /ˈplæn ɪt/
noun
1.
Astronomy.
  1. Also called major planet. any of the eight large heavenly bodies revolving about the sun and shining by reflected light: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, or Neptune, in the order of their proximity to the sun. Until 2006, Pluto was classified as a planet ninth in order from the sun; it has been reclassified as a dwarf planet.
  2. a similar body revolving about a star other than the sun.
  3. (formerly) a celestial body moving in the sky, as distinguished from a fixed star, applied also to the sun and moon.
2.
Astrology. the sun, moon, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, or Pluto: considered sources of energy or consciousness in the interpretation of horoscopes.
Origin
1250-1300
1250-1300; Middle English planete (< Old French planète) < Late Latin planēta, planētēs (found only in plural planētae) < Greek (astéres) planḗtai literally, wandering (stars)
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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Examples from the web for planet
  • But if an object is orbiting another, much larger object that's not a star, it wouldn't count as a planet either.
  • For the first time a spacecraft orbiting a foreign planet has spied--and photographed--some of its kin.
  • The likely rocky planet orbits squarely in its star's habitable zone, making it a prime candidate for life, astronomers report.
  • The tinier the star, the tinier the transiting planet that can be detected.
  • The odd, fiery planet is so close to its star and so large that it is triggering tremendous plasma tides on the star.
  • Astronomers say it's a medium-size planet orbiting an average star.
  • But it was able to photograph only half of the planet in any detail.
  • Astronomers believe they may have discovered the first planet ever detected in another galaxy.
  • Certain travel destinations remind you that you live on a planet-an old, weathered, tectonic-plate-shifting planet.
  • They haven't decided on a name yet, but astronomers announce they've found another planet in our solar system.
British Dictionary definitions for planet

planet

/ˈplænɪt/
noun
1.
Also called major planet. any of the eight celestial bodies, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune, that revolve around the sun in elliptical orbits and are illuminated by light from the sun
2.
Also called extrasolar planet. any other celestial body revolving around a star, illuminated by light from that star
3.
(astrology) any of the planets of the solar system, excluding the earth but including the sun and moon, each thought to rule one or sometimes two signs of the zodiac See also house (sense 9)
Word Origin
C12: via Old French from Late Latin planēta, from Greek planētēs wanderer, from planaein to wander
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for planet
n.

late Old English planete, from Old French planete (Modern French planète), from Late Latin planeta, from Greek planetes, from (asteres) planetai "wandering (stars)," from planasthai "to wander," of unknown origin, possibly from PIE *pele- (2) "flat, to spread" on notion of "spread out." So called because they have apparent motion, unlike the "fixed" stars. Originally including also the moon and sun; modern scientific sense of "world that orbits a star" is from 1630s.

Online Etymology Dictionary, © 2010 Douglas Harper
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planet in Science
planet
  (plān'ĭt)   
A large celestial body, smaller than a star but larger than an asteroid, that does not produce its own light but is illuminated by light from the star around which it revolves. In our solar system there are nine known planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. Because of Pluto's small size—about two-thirds the diameter of Earth's moon—and its unusual orbit, many astronomers believe it should actually be classed as a Kuiper belt object rather than a planet. A planetlike body with more than about ten times the mass of Jupiter would be considered a brown dwarf rather than a planet. See also extrasolar planet, inner planet, outer planet.

planetary adjective
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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planet in Culture

planet definition


An object in orbit around a star. A planet does not give off its own light; rather, it shines by reflecting sunlight. Planets close to the sun are rocky. Those farther out consist mostly of gases and liquids.

Note: There are nine major planets, including the Earth, in orbit around our sun, along with many asteroids. (See solar system.)
Note: Scientists have discovered evidence for the existence of many planets that circle other stars.
The American Heritage® New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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planet in Technology


["An Experiment in Language Design for Distributed Systems", D. Crookes et al, Soft Prac & Exp 14(10):957-971 (Oct 1984)].

The Free On-line Dictionary of Computing, © Denis Howe 2010 http://foldoc.org
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