Source : Free On-Line Dictionary of Computing

interrupt request
     
        (IRQ) The name of an input found on many processors which
        causes the processor to suspend normal instruction execution
        temporarily and to start executing an {interrupt handler}
        routine.  Such an input may be either "{level sensitive}" -
        the {interrupt} condition will persist as long as the input is
        active or "{edge triggered}" - an interrupt is signalled by a
        low-to-high or high-to-low transition on the input.  Some
        processors have several interrupt request inputs allowing
        different priority interrupts.
     
        (1994-12-08)