Definitions

1. noun

A piece of coal that has not been burned and is therefore still hard and black.

“The clinker in the furnace needed to be removed before it could be cleaned.”

2. noun

A small piece of broken brick or stone that has been ejected from a kiln during the firing of bricks.

“The clinker in the brick wall needed to be chipped away before it could be repointed.”

3. verb

To cause something, especially a coal or brick, to be ejected from a kiln or furnace as a clinker.

“The defective kiln was causing bricks to clinker during the firing process.”