canary in a coal mine

== English == === Alternative forms === canary in a coalmine, canary in the coal mine, canary in the coalmine === Etymology === An allusion to caged canaries that miners would carry down into the mine tunnels with them. If dangerous gases, such as carbon monoxide collected in the mine, the gases would kill the canary before killing the miners, thus providing a warning to exit the tunnels immediately. === Pronunciation === === Noun === canary in a coal mine (plural canaries in a coal mine or canaries in coal mines) (idiomatic) Something whose sensitivity to adverse conditions makes it a useful early indicator of such conditions; something which warns of the coming of a greater danger or trouble by a deterioration in its health or welfare. Synonym: miner's canary ==== Related terms ==== ==== Translations ==== === See also ===