← Dictionary

a-canary-in-the-coal-mine

/ə ˈkæn.ə.ri ɪn ðə ˈkɔːl maɪn/
IELTSAcademic
idiom

A warning sign that shows danger or trouble before it becomes obvious. People use it for one small thing that reveals a bigger problem.

  • This delay is a canary in the coal mine.
  • Rising prices are a canary in the coal mine.
  • Her cough was a canary in the coal mine.

Adinary Nuance

A canary in the coal mine is not the same as a simple warning. It is the first small sign of a larger problem that may still be hidden. Writers choose it when they want to show early danger, not just general caution. It often sounds more vivid than words like "warning" or "signal".

In other languages

Vietnamese
Dấu hiệu cảnh báo sớm
Spanish
Señal de alerta temprana
Chinese
早期警示
Japanese
早期警告
Korean
초기 경고 신호

Etymology

The phrase comes from coal mining in the 19th and early 20th centuries. Miners once took canaries underground to warn them about poisonous gas.

Common phrases

a canary in the coal mine forbe a canary in the coal mineuse something as a canary in the coal mine

Synonyms

Related words

Frequently asked questions

Is a canary in the coal mine formal or informal?
It is common in writing and speech. It sounds vivid, so it fits journalism, essays, and business talk.
What is the difference between a canary in the coal mine and a red flag?
A red flag is any warning. A canary in the coal mine is the first small warning of a bigger problem.
Can I use this phrase in business writing?
Yes. It works well when you describe an early sign of risk or decline.
Is this phrase common in modern English?
Yes, but it is more common in writing than in casual conversation.