plan·​et | \ ˈpla-nət How to pronounce planet (audio) \

Definition of planet

1a(1) : any of the large bodies that revolve around the sun in the solar system
(2) : a similar body associated with another star
b : earth usually used with the one of the hottest places on the planet
c : any of the seven celestial bodies sun, moon, Venus, Jupiter, Mars, Mercury, and Saturn that in ancient belief have motions of their own among the fixed stars
2 : a celestial body held to influence the fate of human beings
3 : a person or thing of great importance : luminary
planet table

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Other Words from planet

planetlike \ ˈpla-​nət-​ˌlīk How to pronounce planetlike (audio) \ adjective

Synonyms for planet


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Did You Know?

Planet goes back to ancient Greek planēt- (literally, "wanderer"), which is derived from "planasthai," a Greek verb which means "to wander." The name "planet" was originally applied to any of seven visible celestial bodies which appeared to move independently of the fixed stars - the sun, the moon, Mercury, Venus, Mars, Jupiter, and Saturn. In the 17th century, "planet" began to be used specifically of the rocky or gaseous bodies that orbit around the sun - a definition which excluded the moon and, obviously, the sun, but included the Earth and, as they were discovered, Uranus, Neptune, and Pluto. In 2006, the International Astronomical Union developed a narrower definition of "planet," effectively demoting Pluto to the status of a "dwarf planet," a celestial body that is spherical and orbits the sun but is not large enough to disturb other objects from its orbit.

Examples of planet in a Sentence

our collective responsibility to conserve the planet and its natural resources for future generations
Recent Examples on the Web If protests persuade stores to cut back on this margin-destroying activity, both the planet and profitability would benefit. Andrea Felsted, Fortune, "Black Friday Boycotts in Europe Could Help Retailers’ Bottom Line," 28 Nov. 2019 Climate change is adding to the stresses in some of the planet’s hottest and driest nations. Ian James, azcentral, "Ancient aqueducts in Oman imperiled by modern wells and climate change," 28 Nov. 2019 Over time, the dust and elements stuck together, forming planets and other bodies, including asteroids. Ashley Strickland, CNN, "Ice fossils found in 4.6 billion-year-old meteorite reveal building blocks of our solar system," 26 Nov. 2019 Higher-magnification eyepieces can be useful on planets and the moon, but aren’t totally necessary. Mike Lynch, Twin Cities, "Skywatch: How to buy a telescope for a gift," 24 Nov. 2019 Scientists are confident that the debris stream will be in Earth's path this week because the trail's motion is determined by the gravity of the planets and sun, reported. Meg Jones, Milwaukee Journal Sentinel, "Get ready for rare Unicorn meteor shower that could light up the sky Thursday night. If it's not cloudy in Wisconsin," 20 Nov. 2019 The two films might as well take place on different planets. Anthony Lane, The New Yorker, "The Art of the Awkward Silence in “A Beautiful Day in the Neighborhood”," 15 Nov. 2019 That is why astrobiologists are so keen to identify liquid water on other planets. Robin George Andrews, New York Times, "They Didn’t Find Life in a Hopeless Place," 1 Nov. 2019 Skip to main content SportsPulse: The Astros had home field, the best pitcher on the planet and the experience. Jesse Yomtov, USA TODAY, "Astros' Josh Reddick wants catcher's interference to be reviewable after missed call in Game 1," 23 Oct. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'planet.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of planet

14th century, in the meaning defined at sense 1a

History and Etymology for planet

Middle English planete, from Anglo-French, from Late Latin planeta, modification of Greek planēt-, planēs, literally, wanderer, from planasthai to wander — more at floor

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Time Traveler for planet

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The first known use of planet was in the 14th century

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Last Updated

2 Dec 2019

Cite this Entry

“Planet.” The Dictionary, Merriam-Webster Inc., Accessed 9 December 2019.

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More Definitions for planet


plan·​et | \ ˈpla-nət How to pronounce planet (audio) \

Kids Definition of planet

: any large heavenly body that orbits a star (as the sun)

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