Wiktionary
alt. 1 A caged bird kept caged in mines because its demise provided a warning of dangerous levels of toxic gases. 2 (context idiomatic English) Any thing, especially an organism, whose demise or distress provides an early warning of danger. n. 1 A caged bird kept caged in mines because its demise provided a warning of dangerous levels of toxic gases. 2 (context idiomatic English) Any thing, especially an organism, whose demise or distress provides an early warning of danger.
Usage examples of "miner's canary".
In defense, some large companies go so far as to set aside one ``miner's canary'' among their fleet of computers, and advance its internal calendar a week so that any time-bomb viruses will reveal themselves prematurely before the big day.
But as it was the atmosphere of The Bramfield Arms, it was still one best tested first with a miner's canary, or whatever the sub-marine equivalent might be.
Many people who had got to know Rincewind had come to treat him as a sort of two-legged miner's canary[20] and tended to assume that if Rincewind was still upright and not actually running then some hope remained.