crumb
A small piece which breaks off from baked food (such as cake, biscuit or bread).
A small piece of any other solid substance.
(figuratively) A bit, small amount.
(crumb rubber)
The soft internal portion of bread, surrounded by crust.
A mixture of sugar, cocoa and milk, used to make industrial chocolate.
(slang) A nobody; a worthless person.
(slang) A body louse ((species)).
To cover with crumbs.
To break into crumbs or small pieces with the fingers; to crumble.