v. & n.
v. 1 tr. & intr. break or fall into crumbs or fragments. 2 intr. (of power, a reputation, etc.) gradually disintegrate.
n. 1 Brit. a mixture of flour and fat, rubbed to the texture of breadcrumbs and cooked as a topping for fruit etc. (apple crumble; vegetable crumble). 2 a crumbly or crumbled substance.
[ ME f. OE, formed as CRUMB ]