Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English


English definition of “planet”


noun [C]    /ˈplæn·ɪt/
earth science an extremely large , round mass of matter , such as Earth or Mars , that moves in a circular path around the sun or another star planetary    /ˈplæn·əˌter·i/ adjective [not gradable] earth science planetary scientists
(Definition of planet noun from the Cambridge Academic Content Dictionary © Cambridge University Press)
Focus on the pronunciation of planet

Definitions of “planet” in other dictionaries

Word of the Day


a good knowledge of something, or the fact that you know it so well

Word of the Day


Read our blog about how the English language behaves.

Learn More

New Words

Find words and meanings that have just started to be used in English, and let us know what you think of them.

Learn More