Clinker

A mass composed of several bricks run together by the action of the fire in the kiln.

Scoria or vitrified incombustible matter, formed in a grate or furnace where anthracite coal in used; vitrified or burnt matter ejected from a volcano; slag.

A scale of oxide of iron, formed in forging.

A kind of brick. See Dutch clinker, under Dutch.

a hard brick used as a paving stone