canary in a coal mine
Proposed by a contributor, not yet supported by evidence.
Meaning · English
Early warning of potential danger or problem
Literally: bird in a tunnel
Where it’s used:
Used
Widespread English
Examples
The increase in layoffs is the canary in a coal mine for the company's financial troubles
AI-drafted example auto-approved by rule (illustrative, not a corpus attestation)
Sources & notes
Listed in Wiktionary’s “English idioms” category (retrieved 2026-07-29); definition pending editorial review. Definition drafted by AI (@cf/meta/llama-3.3-70b-instruct-fp8-fast) and auto-approved by rule on 2026-07-30; pending editor spot-check.
Common questions
What does “canary in a coal mine” mean?
Early warning of potential danger or problem Literally: bird in a tunnel
Is “canary in a coal mine” formal or informal?
No register label has been reviewed yet — treat it as neutral and check the usage notes above.