reg·​o·​lith | \ ˈre-gə-ˌlith How to pronounce regolith (audio) \

Definition of regolith

: unconsolidated residual or transported material that overlies the solid rock on the earth, moon, or a planet

Examples of regolith in a Sentence

Recent Examples on the Web

Over perhaps a billion years, a drizzle of tiny micrometeorites hitting the moon will dissolve the boulders into finer soils called regolith. Quanta Magazine, "Asteroid Rate Jumped in Solar System’s Past," 17 Jan. 2019 And the Pragyan rover’s two spectrometers would have revealed the composition of lunar regolith, or soil, across the rover’s traverse. Jonathan O'callaghan, Scientific American, "India Loses Contact with Lunar Lander," 6 Sep. 2019 The regolith, on the other hand, cools quickly, like beach sand after sunset. Quanta Magazine, "Asteroid Rate Jumped in Solar System’s Past," 17 Jan. 2019 Though the moon's surface is mostly made up of the fine regolith, various rocks are scattered throughout. Ryan W. Miller, USA TODAY, "Buzz Aldrin and Neil Armstrong put a flag on the moon. Here's what you can and can't see in the iconic photo," 19 July 2019 To call these 382 kilograms of stone and regolith (the thick layer of crushed rock and dust that covers the surface of the moon and other planetary bodies) a treasure trove does not do them justice. Erica Jawin, Scientific American, "Apollo’s Bounty: The Science of the Moon Rocks," 2 July 2019 The helium 3 deposits common in areas of the top layer of lunar regolith could power fusion reactors. Adam Mann, Scientific American, "The New Scramble for the Moon," 26 June 2019 Then, using a rake, Schmitt scraped the powdery surface, lifting a rock later named troctolite 76536 off the regolith and into history. Quanta Magazine, "What Made the Moon? New Ideas Try to Rescue a Troubled Theory," 2 Aug. 2017 That's what will happen, most likely next week, if everything below the surface is regolith. David Grossman, Popular Mechanics, "To Understand How the Earth Formed, and How It Might Disappear, NASA Is Drilling on Mars," 21 Feb. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'regolith.' 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 regolith

1897, in the meaning defined above

History and Etymology for regolith

Greek rhēgos blanket + English -lith; akin to Greek rhezein to dye — more at raga

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Last Updated

7 Oct 2019

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Time Traveler for regolith

The first known use of regolith was in 1897

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