n. A morsel: specifically, a minute piece of bread or other friable food broken off, as in crumbling it; hence, a very small fragment or portion of anything.n. The soft inner part of a loaf of bread or cake, as distinguished from the crust.To break into small pieces with the fingers: as, to crumb bread into milk.. To crumble bread into; prepare or thicken with crumbs of bread.In cookery, to cover or dress with breadcrumbs, as meat, etc.; bread.Same as crump.