Definition of "clinker" [clink•er]

• The incombustible residue, fused into an irregular lump, that remains after the combustion of coal. (noun)
• A partially vitrified brick or a mass of bricks fused together. (noun)
• An extremely hard burned brick. (noun)
• Vitrified matter expelled by a volcano. (noun)
• Slang A sour note in a musical performance: hit a clinker. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "If clinker is found on the ground, a coal seam is bound to be underneath."
• "The clinker is that the chain decides which Canadian authors they will display and advertise from a list of authors that the six publishers submit."
• "The wreck is described as clinker built, a shipbuilding style which dates back to the Viking era, but used for centuries afterwards."