clinker

1. A very hard brick used for paving customarily made in the Netherlands.
2. A mass of bricks fused together by intense heat.
3. Slag or ash produced by intense heat in a furnace, kiln or boiler that forms a hard residue upon cooling.
4. An intermediate product in the manufacture of Portland cement, obtained by sintering limestone and alumino-silicate materials such as clay into nodules in a cement kiln.
5. Hardened volcanic lava.
6. A scum of oxide of iron formed in forging.

verb

To convert or be converted into clinker.

1. Someone or something that clinks.
2. (in the plural) Fetters.

1. A style of boatbuilding using overlapping planks.

   clinker planking; a clinker dinghy