Cách sử dụng
The word 'canary' is a name of a small and brightly colored bird. It is often used in conversation to refer to a warning of danger or potential danger. This is because in the past, miners used to take canaries with them into mines as a warning signal; if there was danger such as poisonous gas, the canaries would die before the miners did, giving them time to escape. So, when someone says "like a canary in a coal mine" or "a canary in a cage", they are referring to someone or something that is used to detect danger before others are affected by it.