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
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.
As we chatted on our way to and from the lobby, I thought about a long-ago Coke business trip—a wartime journey to North Africa—that eventually led to the company’s planetary dominance.
From The Wall Street Journal ● Jul. 19, 2026
This was a planetary event for America to prove that its cultural hegemony could absorb the world’s most popular sport.
From The Wall Street Journal ● Jul. 18, 2026
"We know that there's much more lithium in planetary material than there is in stars. So if a star eats a planet, it's going to take on a bunch of lithium."
From Science Daily ● Jul. 16, 2026
That finding suggests that planetary engulfment may not be the only process capable of enriching a star with lithium, creating another question for astronomers to investigate.
From Science Daily ● Jul. 16, 2026
We are not yet certain how many planetary systems there are, but there seem to be a great abundance.
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.
