crum·ble / ˈkrəmbəl/ • v. [intr.] break or fall apart into small fragments, esp. over a period of time as part of a process of deterioration: the plaster started to crumble. ∎  [tr.] cause (something) to break apart into small fragments. ∎  (of an organization, relationship, or structure) disintegrate gradually over a period of time.• n. Brit. a mixture of flour and butter that is rubbed to the texture of breadcrumbs and cooked as a topping for fruit. ∎  a dessert made with such a topping and a particular fruit: rhubarb crumble.

crumble Flour, fat, and sugar (a rubbed‐in plain cake mix) baked as a topping over fruit instead of pastry. For savoury crumble the sugar is omitted and cheese and seasoning are added.