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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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 As the planet cooled in subsequent millennia, these canids expanded their range, evolving into foxes and eventually reaching every continent excepting Antarctica. David James, Anchorage Daily News, "New book explores the hidden world of the fabled yet enigmatic fox," 23 Feb. 2020 Considering the planet holds approximately 8 billion people, that would be about 624 million of us with unhealthy relationships with food, a growing number of those in Asia and Middle Eastern countries. Sandee Lamotte, CNN, "She learned to love eating -- and herself -- despite a lifetime of fat shaming," 22 Feb. 2020 The study of ancient methane emissions, on the other hand, is consistent with her research, which shows that permafrost lakes didn’t release vast quantities of methane as the planet left its last ice age. Warren Cornwall, Science | AAAS, "Humans are a bigger source of climate-altering methane, new studies suggest," 20 Feb. 2020 Lawrence will star in Adam McKay’s Don’t Look Up, an upcoming comedy about two scientists’ struggle to convince the world that an asteroid will hit the planet imminently. Kaitlin Reilly,, "Good News: Jennifer Lawrence Is Headed To Netflix," 19 Feb. 2020 Also backed by Discovery are several missions like Lucy and Psyche that have yet to leave Earth—both of which will get scientists up close and personal with some asteroids that could help us understand how the planets formed. Katherine J. Wu, Smithsonian Magazine, "Where Will NASA Explore Next? Here Are the Four Shortlisted Missions," 18 Feb. 2020 The current mark is the station itself, which circles about 254 miles (409 km) above the planet. Tim Fernholz, Quartz, "Ready to buy a trip to orbit from Elon Musk?," 18 Feb. 2020 Be careful as the planet of communication could be fuzzing up the works., "Horoscope," 14 Feb. 2020 Newer entrants like Project Kuiper, Starlink, and SoftBank Group's OneWeb plan to use hundreds or even thousands of smaller, cheaper satellites in orbits that are only a few hundred miles up to blanket the planet with coverage. Aaron Pressman, Fortune, "Exclusive: Space Internet startup Astranis raises $90 million," 13 Feb. 2020

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

25 Feb 2020

Cite this Entry

“Planet.” Dictionary, Merriam-Webster, Accessed 26 Feb. 2020.

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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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