bus

The communication path used between the component parts of a computer.

In computing, the electrical pathway through which a computer processor communicates with some of its parts and/or peripherals. Physically, a bus is a set of parallel tracks that can carry digital signals; it may take the form of copper tracks laid down on the computer's printed circuit boards (PCBs), or of an external cable or connection.

A computer typically has three internal buses laid down on its main circuit board: a data bus, which carries data between the components of the computer; an address bus, which selects the route to be followed by any particular data item travelling along the data bus; and a control bus, which is used to decide whether data is written to or read from the data bus. An external expansion bus is used for linking the computer processor to peripheral devices, such as modems and printers.