Clinker has several meanings:

• Clinker (boat building), construction method for wooden boats

• Clinker is a general name given to waste from industrial processes - particularly those that involve smelting metals or burning fossil fuels. Clinker often forms a loose, black deposit that can consist of coke, coal, slag, charcoal, grit and other waste materials.

• Cement manufacturing clinker is a kilned then quenched product primarily composed of tricalcium silicate, dicalcium silicate, tricalcium aluminate, and calcium aluminoferrite.

• Residue from burning coal.

• Humphry Clinker, title character of Tobias Smollett's 1771 novel The Expedition of Humphry Clinker

See also,

• Clinker brick, rough dark coloured bricks

Klinker | Brique | Klinker (steen)