plan·​e·​tary | \ˈpla-nə-ˌter-ē \

Definition of planetary 

1a : of, relating to, being, or resembling a planet

b : erratic, wandering

c : having a motion like that of a planet planetary electrons

d : immense the scope of this project has reached planetary proportions

2a : of, relating to, or belonging to the earth : terrestrial

b : global, worldwide planetary politics

3 : having or consisting of an epicyclic train of gear wheels

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Examples of planetary in a Sentence

a positively planetary new shopping development

Recent Examples on the Web

Micheli said computer models suggest objects typically are ejected during the formation of planetary systems, and that most of these castaways should be comets given their location on the frigid outskirts of their systems. Washington Post, "Comet or asteroid? Scientists ID interstellar visitor," 27 June 2018 The compound is stirred into the comet at its formation, a fingerprint of the early planetary system. Nola Taylor Redd, Scientific American, "Interstellar Mystery Object Now Thought to Be a Comet," 27 June 2018 Researchers are hoping this technique, applied to other disks, will reveal more planets in formation and help us understand how gravity molds primordial clouds into planetary systems, including our own. Daniel Clery, Science | AAAS, "This distant disk may contain the youngest exoplanets ever detected," 14 June 2018 Most planetary systems occur around the dim, reddish M-dwarf stars, not the yellowish G-type stars like our sun. Eva Botkin-kowacki, The Christian Science Monitor, "How Kepler opened our eyes to the vastness of our galactic neighborhood," 16 Apr. 2018 But geophysicists and planetary scientists have long suspected that real oceans and atmospheres often behave like flat systems, making the intricacies of two-dimensional turbulence surprisingly relevant to real problems. Joshua Sokol, WIRED, "Flattened Fluids Help Scientists Understand Oceans and Atmospheres," 7 July 2018 In 2010, Seiichi Nagihara, a planetary scientist at Texas Tech University in Lubbock, decided to try and find out, once and for all, why the lunar surface temperature started to rise soon after the Apollo missions started. Brigit Katz, Smithsonian, "Astronauts’ Footprints May Have Warmed the Moon," 14 June 2018 Climate change itself is listed as one of the planetary boundaries. Chelsea Harvey, Scientific American, "Tree Farms Will Not Save Us from Global Warming," 13 Mar. 2018 Vietnam stands out of the crowd, meeting six of the well-being targets while transgressing only two planetary boundaries. Cathleen O'grady, Ars Technica, "If we gave everyone a decent standard of living, could we sustain it?," 6 Feb. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'planetary.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of planetary

1607, in the meaning defined at sense 1a

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Statistics for planetary

Last Updated

7 Nov 2018

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The first known use of planetary was in 1607

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English Language Learners Definition of planetary

: of or relating to planets


plan·​e·​tary | \ˈpla-nə-ˌter-ē \

Kids Definition of planetary

1 : of or relating to a planet

2 : having a motion like that of a planet

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Comments on planetary

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something that serves to warn or remind

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