clinker
nounUK /ˈklɪŋkə/
US /ˈklɪŋkər/
A clinker is a hard, stony lump left over after coal or rock has been burned or melted.
The old furnace was full of clinkers that had to be scraped out.
OTHER MEANINGS
2. A very hard brick used for paving, made by burning clay until it fuses.
The garden path was laid with blue clinkers.
3. A mistake or wrong note, especially in music or a performance.
The pianist hit a clinker near the end of the piece.
4. A type of strong, heavy sailing boat used in the past.
The clinker raced across the harbor with the wind behind it.
5. A hard mass of fused material in a cement kiln.
Cement plants grind the clinker into fine powder.