noun

A canary is a small, colorful bird that people used to keep as pets. Long ago, coal miners would take canaries down into the mines with them. The canaries would chirp and sing happily when the air was safe. But if the air started to become dangerous, the canaries would stop singing and fall asleep. This was a signal to the miners that the air was becoming poisonous and they needed to leave the mine quickly to avoid getting hurt. So, a canary is like a little helper that tells people when something is wrong, just by being there and reacting to their environment.

Example

1. The canary's singing brought joy to the room.
2. The coal miners brought a canary with them to the mine for safety.
3. The canary stopped singing, warning the miners of dangerous gas.