In the world of software development, a "bug" is an error or flaw in the code that causes a program to not function as it should. They can be small details, like a button that doesn't respond, or serious flaws that can cause the entire system to collapse. To fix them, developers perform "debugging," which is the process of detecting and correcting these errors. Tools such as debuggers, logs, and automated tests help find and eliminate bugs before they reach end users.