coal
n//koʊl//kol, stenkol, kolbit, glöd
(uncountable) A black or brownish black rock formed from prehistoric plant remains, composed largely of carbon and burned as a fuel.
(countable) A piece of coal used for burning (this use is less common in American English)
(military slang, WWI, _, –, _, WWII) Bombs emitting black smoke on impact.