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


Visit the Thesaurus for More 

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 word 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 line with astronomical discovery and advancement, planet began to be used specifically of the rocky or gaseous bodies that orbit around the sun—a definition which excluded the moon and 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 Market capitalizations fluctuate frequently: earlier this year, Apple (AAPL) hit the $3 trillion mark, becoming the first to do so and making it by far the most valuable company on the planet. Michelle Toh, CNN, 12 May 2022 Only a few dozen people on the planet have had neural interfaces embedded in their cortical tissue as part of long-term clinical research. New York Times, 12 May 2022 InSight Mars lander has detected the largest quake ever observed on another planet. Julia Musto, Fox News, 11 May 2022 Lincoln Tavern & Restaurant Is there a happier kid on the planet than one who’s presented with a stack of Fruity Pebbles pancakes? Pamela Wright,, 6 May 2022 But in the Marvel Cinematic Universe, Waldron now gets a chance to twist and bend the laws of one of the most lucrative entertainment empires on the planet. Daniel Arkin, NBC News, 5 May 2022 In contrast to the historic metropolises of Rome and Florence, the mountainous northern region of Trentino, South Tyrol feels like another planet. Washington Post, 29 Apr. 2022 In the original comic, Valentine Jones, a.k.a. Ebon, is an alien hailing from the planet of Nyta, where every resident is Black. Danielle Broadway, Los Angeles Times, 28 Apr. 2022 However, polar species are likely to go globally extinct, as their habitats will disappear from the planet entirely. Doyle Rice, USA TODAY, 28 Apr. 2022 See More

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.

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

Buying Guide

Study celestial bodies with the best telescopes for beginners from our Reviews team.

Learn More About planet

Time Traveler for planet

Time Traveler

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

See more words from the same century

Listen to Our Podcast About planet

Dictionary Entries Near planet

plane symmetry


plane table

See More Nearby Entries 

Statistics for planet

Last Updated

14 May 2022

Cite this Entry

“Planet.” Dictionary, Merriam-Webster, Accessed 19 May. 2022.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

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)

More from Merriam-Webster on planet

Nglish: Translation of planet for Spanish Speakers

Britannica English: Translation of planet for Arabic Speakers Encyclopedia article about planet


Test Your Vocabulary

Name That Color

  • a light greenish blue color
  • Name that color:
Spell It

Can you spell these 10 commonly misspelled words?

Universal Daily Crossword

A daily challenge for crossword fanatics.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!