An Application Interface Driver (AID) is a type of software driver that allows applications to communicate with hardware or system components through a standardized interface. In the context of Windows drivers, an AID typically serves as a bridge between software applications and hardware devices, enabling the application to send commands or receive data from the hardware in a way that the hardware understands.

In simpler terms, an Application Interface Driver helps applications use hardware features by providing a communication layer between the application and the device. It can be used for various types of hardware, such as graphics cards, sound devices, printers, or even specific peripherals.