In reference to computer hardware, a port is an outlet into which devices can be plugged, connecting the computer to peripherals such as keyboards, scanners and mice. The connection that happens between the port and device (usually done through a cable) allows signals to be sent back and forth, such as a mouse click or a print job.
There are several different types of ports, characterized by the shape and size of the connection point and the way they transmit data. Serial ports consist of one pair of wires, send and receive data a single bit at a time, and are commonly used to connect mice to computers. Parallel ports have many sets of wires, simultaneously send multiple bits, and connect computers to printers. USB ports are very common now and connect devices like keyboards, mice and storage devices.
Ports make computers much more useful by enabling their interaction with many other devices.
