regolith

noun

reg·​o·​lith ˈre-gə-ˌlith 

: 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

There’s regolith and a couple of Chinese landers—Chang’e 4 in January 2019 and Chang’e 6 in June 2024—and not much else. —Harry Goldstein, IEEE Spectrum, 1 Feb. 2026

Elements from our planet’s atmosphere have made their way into moon dust, also called regolith, on a pathway created by the Earth’s magnetic field. —Devika Rao, TheWeek, 27 Jan. 2026

Perseverance has been dutifully scouting out Mars' Jezero Crater since early 2021, on the prowl for signs of ancient life on the Red Planet, gathering samples of rock, regolith, and atmosphere for eventual return to Earth. —Leonard David, Space.com, 12 Jan. 2026

With the exception of the biological components found in Earth’s topsoil, the composition of the Moon’s regolith is identical to the composition of Earth’s crust. —Big Think, 6 Nov. 2025

Word History

Etymology

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

First Known Use

1897, in the meaning defined above