regolith

noun

1. mantle rock.

noun

1. the layer of loose material covering the bedrock of the earth and moon, etc, comprising soil, sand, rock fragments, volcanic ash, glacial drift, etc

n.

1897, from Greek rhegos “rug, blanket,” from PIE *reg- (3) “to dye” (see raga) + lithos “stone” (see litho-).

1. The layer of rock and mineral fragments that rests on bedrock and is produced by the weathering of rocks. Regolith constitutes the surface of most land.