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

However, when the Apollo missions brought back samples from the moon between 1969 and 1972, scientists found that the lunar regolith was bone dry. —Keith Cooper, Space.com, 14 Apr. 2026

The image, taken in the Martian regolith of the Paraitepuy Pass — a narrow gap in the Gale Crater situated on the slopes of Mount Sharp, was originally photographed on August 7, 2022, by the Mast camera onboard NASA’s Mars Curiosity rover. —Ryan Brennan april 2, Kansas City Star, 2 Apr. 2026

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

This camera will be used to estimate helium-3 quantities and concentration in Moon dirt, or regolith. —Eric Berger, ArsTechnica, 3 Mar. 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