Input/output
Alternatively referred to as I/O, Input/output is any software or hardware device that is designed to send and receive data to and from a computer hardware component. For example, when referring to hardware, a computer mouse is only an input device, it can send data but doesn't receive any data back, and a computer monitor is an output device, it can display information but doesn't send data back to the computer. A good example of an I/O device is a Modem that connects to the Internet and sends and receives information.
Also see: Input, Output, I/O device, I/O ports, Input/Output supervisor