The correct answer is Interrupt. An interrupt is a signal from a device attached to a computer or from a program within the computer that requires the operating system to stop and figure out what to do next. Almost all personal computers today are interrupt-driven - that is, they start down the list of computer instructions in one program (perhaps an application such as a word processor) and keep running the instructions. After the interrupt signal is sensed, the computer either resumes running the current program or begins running another program. Hence, the signal informing a program that an event has occurred is known as Interrupt.