An interrupt is the way a device halts the kernel, telling it that something interesting or important has happened. These are called IRQs on Linux systems. The main advantage interrupts offer is to avoid device polling. It is up to the device to tell if there is a change in its state; it is not up to us to poll it.
In order to get notified when an interrupt occurs, you need to register to that IRQ, providing a function called an interrupt handler that will be called every time that interrupt is raised.
