An interrupt signal is a signal sent to the processor by hardware or software to indicate that an event needs immediate attention. This allows the processor to pause its current activities and address the urgent task, such as responding to user input or handling a hardware malfunction. Interrupt signals help manage multiple tasks efficiently, ensuring that critical operations are prioritized. When an interrupt signal is received, the processor saves its current state and executes a special routine called an interrupt handler. After the handler completes its task, the processor can resume its previous activities. This mechanism is essential for maintaining smooth operation in systems like computers and embedded devices.