gravel (n.)

"stone in small, irregular fragments," early 13c., from Old French gravele "sand, gravel; sea-shore; sandy bed of a river," diminutive of grave "sand, seashore" (Modern French grève), possibly from Celtic *graw- (compare Welsh gro "coarse gravel," Breton grouan, Cornish grow "gravel"), perhaps ultimately from PIE *ghreu- "to rub, grind" (see grit (n.)). Gravel-crusher was World War I slang for "infantryman."