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 planet (audio) \ adjective

Synonyms for planet


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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 By working together, modern business leaders can generate profits while protecting our planet, expanding opportunities for more people, and advancing global prosperity. Carmine Di Sibio, Fortune, "Stakeholder capitalism isn’t a new idea," 16 Apr. 2021 That promise is now a reality, with California and partners set to launch, by 2023, two satellites to spot and monitor plumes of planet-warming carbon dioxide (CO2) and methane. Paul Voosen, Science | AAAS, "California to hunt greenhouse gas leaks and super-emitters with monitoring satellites," 15 Apr. 2021 Seagrasses play a large role in regulating ocean environments, storing more than twice as much carbon from planet-warming carbon dioxide (CO2) per square mile as forests do on land, according to a 2012 study in the journal Nature Geoscience. NBC News, "Shrinking sea meadows add to carbon emission concerns," 8 Apr. 2021 That means more wildfires, which could release massive amounts of planet-warming gas. Matt Simon, Wired, "More Lightning in the Arctic Is Bad News for the Planet," 7 Apr. 2021 By cutting down and shifting some of that electricity use to different parts of the day, the state hopes to lessen the planet-warming emissions produced overall and make the grid more flexible. Taylor Kate Brown, San Francisco Chronicle, "PG&E is changing how your electricity bill works - here's everything you need to know," 19 Mar. 2021 Coal, oil and natural gas generate planet-warming carbon dioxide when burned. The Economist, "Toothpaste in your tank Hydrogen goop could be a more convenient fuel than hydrogen gas," 27 Feb. 2021 But the pledges made then by nearly every country on Earth to cut their planet-warming emissions will no longer cut it. CBS News, "John Kerry says Earth has 9 years to avert the worst consequences of climate crisis: "There's no faking it on this one"," 19 Feb. 2021 The shift away from coal power had a significant impact on global emissions of planet-warming carbon dioxide, the researchers said, and could lead to an acceleration of the global shift toward renewable energy. Veronica Penney New York Times, Star Tribune, "Coal-fired power takes a beating during the pandemic, study finds," 8 Feb. 2021

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

20 Apr 2021

Cite this Entry

“Planet.” Dictionary, Merriam-Webster, Accessed 20 Apr. 2021.

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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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