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

The regolith also lacks the microbiome found in Earth soils, and its powder-like consistency doesn't allow water to easily filter through it, according to the paper. —Julia Jacobo, ABC News, 5 Mar. 2026

Problem with regolith Moon dirt, or lunar regolith, is a hostile host. —Mrigakshi Dixit, Interesting Engineering, 5 Mar. 2026

However, even below 75% regolith, things were not perfect. —Keith Cooper, Space.com, 5 Mar. 2026

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

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