1. To break into small pieces or crumbs, eg crumble the biscuits over the top of the dessert or crumble the bread and add to the remaining stuffing ingredients.
2. A sweet or savoury topping usually sprinkled over fruit, meat or vegetables, eg a sweet crumble consists of a mixture of flour, sugar and fat combined together to resemble breadcrumbs and then sprinkled over fruit and baked, a savoury crumble consists of breadcrumbs combined with chopped onion cooked in butter, herbs and seasoning which is sprinkled over minced meat or chopped vegetables and baked.
3. The name of a dish that is topped with a mixture resembling crumbs, eg apple crumble, minced beef crumble.