simple past tense and past participle of burn the coal

plural of coal merchant

(dated) A person who deals in coal, either on a large scale or in a particular locality, where coal was weighed and bagged by the merchant, delivered to households and tipped into a coal bunker.

(geology) The time period with few coal deposits from the Permian to middle Jurassic.

(informal) lignite

(idiomatic) Something whose sensitivity to adverse conditions makes it a useful early indicator of such conditions; something which warns of the coming of greater danger or trouble by a deterioration in its health or welfare.

Alternative form of canary in a coal mine

plural of canary in the coal mine

plural of canary in a coal mine

(military, slang) a style of soldier's helmet that looks the same as or similar to the helmet used by current Chilean soldiery, German soldiery at the end of WWI and during WWII, and Chinese soldiery during the Second Sino-Japanese War