gravel: [13] Gravel is of Celtic origin. It has been traced to a prehistoric Celtic *gravo- ‘gravel’, never actually recorded but deduced from Breton grouan and Cornish grow ‘soft granite’. French borrowed it as grave ‘gravel, pebbles’ (perhaps the source of the English verb grave ‘clean a ship’s bottom’ [15], now encountered virtually only in graving dock, from the notion of ships being hauled up on to the pebbles of the seashore for cleaning). The Old French diminutive of grave was gravelle – whence English gravel. [gravel etymology, gravel origin, 英语词源]