planetary
Americanadjective
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of or relating to a planet
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mundane; terrestrial
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wandering or erratic
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astrology under the influence of one of the planets
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(of a gear, esp an epicyclic gear) having an axis that rotates around that of another gear
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(of an electron) having an orbit around the nucleus of an atom
noun
Other Word Forms
Derived Forms
Etymology
Origin of planetary
From the Latin word planētārius, dating back to 1585–95. See planet, -ary
Explanation
The adjective planetary has to do with any astronomical body that revolves around a star — including the earth. Rather than a circle, planetary motion takes us in an elliptical shape around the sun. In science, planetary usually describes the attributes or motion of planets. It's also used for anything that behaves in a similar way, like planetary electrons, which revolve around their atomic nucleus as if they were tiny planets. You can also talk about things that affect our entire planet using this word: "She worries a lot about the planetary effects of climate change."
Vocabulary lists containing planetary
myPerspectives 7.2
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-ary
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
He added: "The clock is ticking if we want to halt the worst effects of planetary warming but there is still time."
From BBC • Jun. 9, 2026
This event is known as a planetary conjunction.
From Science Daily • Jun. 3, 2026
The Dumbbell Nebula, also known as Messier 27, holds a special place in astronomy history as the first planetary nebula ever discovered.
From Science Daily • Jun. 3, 2026
As telescopes become more powerful, astronomers continue discovering increasingly unusual planetary systems across the galaxy.
From Science Daily • May 21, 2026
Perhaps organisms that float in dense planetary atmospheres will be very much like us in their atomic composition, except they might not have bones and therefore not need much calcium.
From "Cosmos" by Carl Sagan
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
