Looking into the interesting origins of some commonly used software engineering terms.
This term originated from coal mining and the phrase "canary in the coal mine" which means "an early indicator of potential danger or failure". Canary birds have a lower tolerance to toxic gases than humans, so they were used to alert miners when these gases reached dangerous levels inside the mine. The presence of dangerous gases would kill the canary before it could kill the miners, giving them time to escape.
The term smoke testing originates from a basic type of hardware testing in which a device passes the test if it doesn't catch fire the first time it turns on.
The popular agile framework is named after a scrum in rugby, in which the team work together to move forward.
The Waterfall Model is a linear application development model that uses rigid phases: When one phase ends, the next begins.
Hence the term "waterfall", once the water falls down, it cannot go back up.
Back in the day when punched card coding was the thing, one actually had to put a patch of tape/cardboard over a wrongly punched hole in order to fix a bug.
This came from the children's story Hansel and Gretel, where they leave physical bread crumbs on their steps in order to find their way back.
This term comes from the concept of physical walls being barriers to slow the spread of fire until emergency services can extinguish it. Similarly, network security firewalls are intended to slow the spread of web threats.