interrupt

In computing, a signal received by the computer's central processing unit that causes a temporary halt in the execution of a program while some other task is performed. Interrupts may be generated by the computer's internal electronic clock (clock interrupt), by an input or output device, or by a software routine. After the computer has completed the task to which it was diverted, control returns to the original program.

For example, many computers, while printing a long document, allow the user to carry on with other work. When the printer is ready for more data, it sends an interrupt signal that causes the computer to halt work on the user's program and transmit more data to the printer.