A hardware interrupt is something that happens inside a computer that tells it to pause what it is doing and look for something else. It's like a person interrupting you when you are doing your homework. The computer looks at the interruption and then does something special that was asked for by the interruption. For example, if you had a printer connected to your computer and it wanted to print something, it would send a hardware interrupt to let the computer know it needs to be printed right away. The computer would then pause what it was doing and print the document.