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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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 Perhaps most importantly, Sojourner demonstrated the successful use of the first wheeled rover vehicle on another planet. Ashley Strickland, CNN, "Ingenuity Mars helicopter: The historic journey to fly on another planet," 1 Apr. 2021 Perseverance was the first ever spacecraft to perform an entirely autonomous ultraprecise landing on another planet. Leo Deluca, Scientific American, "Ingenuity's 'Wright Stuff': A Piece of the Wright Flyer Will Soar on Mars," 1 Apr. 2021 The president’s focus on climate change is centered, however, on modernizing and transforming the United States’ two largest sources of planet-warming greenhouse gas pollution: cars and electric power plants. New York Times, "Biden Details $2 Trillion Plan to Rebuild Infrastructure and Reshape the Economy," 31 Mar. 2021 While environmentalists maintain that reusing or reducing packaging is better for the planet than recycling or composting, Bailey said wanting to go green is not enough to get the average consumer to opt for reusables. Richard Chin, Star Tribune, "Minneapolis restaurants offer takeout food without a side of guilt for using wasteful containers," 29 Mar. 2021 Bill Gates, who recently suggested the world should eat 100 percent synthetic beef and said bitcoin is bad for the planet, has set his sights on a new foe: the sun. Caroline Delbert, Popular Mechanics, "Bill Gates Is Thinking About Dimming the Sun," 26 Mar. 2021 The main goal of the helicopter is simply to test out flight capabilities on another planet. Catherine Thorbecke, ABC News, "NASA to attempt history-making helicopter flight on Mars," 24 Mar. 2021 Cow burps are full of the powerful planet-warming gas methane, but new research finds that adding seaweed to beef cow diets can reduce their methane emissions by as much as 82 percent, reports Oliver Milman for the Guardian. Alex Fox, Smithsonian Magazine, "Seaweed-Fed Cows Burp Less Planet-Warming Methane," 23 Mar. 2021 Listening to the seismic waves picked up by InSight, scientists measured the size of Mars’s core, the first time this was done for another planet. David Bressan, Forbes, "Mars Becomes The First Inner Planet After Earth To Have Its Core Measured," 18 Mar. 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

8 Apr 2021

Cite this Entry

“Planet.” Dictionary, Merriam-Webster, Accessed 14 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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