Definition of planet
1a : 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 starsb (1) : any of the large bodies that revolve around the sun in the solar system (2) : a similar body associated with another starc : earth —usually used with the
2 : a celestial body held to influence the fate of human beings
3 : a person or thing of great importance : luminary
planetlikeplay \ˈpla-nət-ˌlīk\ adjective
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Examples of planet in a Sentence
our collective responsibility to conserve the planet and its natural resources for future generations
Recent Examples of planet from the Web
Fonsi said in a statement that streaming has helped his music reach every corner of the planet.
A giant asteroid crashing into our planet would instantly kill off millions of animals.
The priority for the planet is to stop net emissions of greenhouse gases, especially carbon dioxide.
Saudi Arabia, one of the world’s largest per capita emitters of planet-warming emissions, has always been a reluctant participant in climate discussions.
Mercury remains our solar system's least studied inner planet, with only NASA's Mariner 10 and MESSENGER probes getting prior looks.
Venus, the planet of love and beauty, makes its annual stop in your sign beginning Tuesday.
Download an astronomy app (try NASA app or The Night Sky) and see how many constellations — and maybe even a planet or two — the kids can spot.
New on DVD Power Rangers PG Five teens have been endowed with super powers but must unify to fight off alien invaders bent on destroying our planet Earth.
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.
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.
PLANET Defined for Kids
Definition of planet for Students
: any large heavenly body that orbits a star (as the sun)
History for planet
Most stars seem to stay in fixed positions night after night. There are certain heavenly bodies, the planets, that look very much like stars but are not. They seem to wander about among the fixed stars. The ancient Greeks gave them the name planētes, meaning “wanderers.” The English word planet comes from this Greek word.
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