معنی کلمه the crust

We saved a few crusts of bread for the birds.

Who knows but if our instruments were delicate enough we might detect an undulation in the crust of the earth ?

A puritan may go to his brown -bread crust with as gross an appetite as ever an alderman to his turtle .

The fundamental basis of geography is the vertical relief of the earth's crust , which controls all mobile distributions .

All grass and weeds must be kept down , and the crust must be broken after every rain , but these seem to be the only principles upon which all agree .

It is characterized by blisters which crust over.