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

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 Only a small sliver of the moon was visible during the eclipse as about 97% of the moon disappeared into Earth’s shadow as the sun and moon pass opposite sides of the planet, EarthSky reported. Staff And Wire Reports, oregonlive, 19 Nov. 2021 More than half a trillion dollars would go toward shifting the U.S. economy away from fossil fuels to renewable energy and electric cars, the largest investment ever to slow the warming of the planet. New York Times, 19 Nov. 2021 Even if that transpires, most of the planet’s surface is ocean, suggesting that a space rock is most likely to land in the middle of nowhere. Robin George Andrews, Scientific American, 18 Nov. 2021 The auction was held less than two weeks after President Joe Biden pushed countries around the world to make collective sacrifices for the sake of the planet at the COP26 climate summit in Glasgow. Lucien Bruggeman, ABC News, 18 Nov. 2021 Led by samurai Hasekura Tsunenaga and Franciscan monk Luis Sotelo, the expedition spent seven years traveling a third of the planet, marking an early form of globalization. Los Angeles Times, 17 Nov. 2021 The extraction and burning of fossil fuels is the most significant contributor to the warming of the planet. Matt Reynolds, Wired, 16 Nov. 2021 The site alongside the River Clyde, where delegates from every corner of the planet had gathered to try to save it, went from crowded to nearly deserted. Compiled Democrat-gazette Staff From Wire Reports, Arkansas Online, 14 Nov. 2021 But world leaders failed on several key points, including steps that limit the warming of the planet to no more than 1.5 degrees Celsius by the end of this century, as set by the Paris Agreement. Sabrina Shankman,, 13 Nov. 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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The first known use of planet was in the 14th century

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Dictionary Entries Near planet

plane symmetry


plane table

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Last Updated

22 Nov 2021

Cite this Entry

“Planet.” Dictionary, Merriam-Webster, Accessed 2 Dec. 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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