in geology, 1795, "process of erosion" (a sense now obsolete), from Latin detritus "a wearing away," from detri-, stem of detere "wear away," from de "away" (see de-) + terere "to rub, wear" (from PIE root *tere- (1) "to rub, turn"). Sense of "loose fragments of rock produced by erosion" is 1802, probably from French detritus; incorrect, in any case. Figurative or transferred sense of "waste material, debris" is by 1834. Related: Detrital; detrited; detrition.