A bus is a parallel circuit that transfers electrical impulses among the functional components within a computer system, including the microprocessor, disk-drive controller, main memory, input/output ports, and so on, allowing each device to send and receive information. The computer's microprocessor usually controls data traffic on the bus. Most modern computers are based on this von Neumann architecture: central processor connected to memory via a bus.

One possible source of the term bus is the electrical engineering term "bus bar" (a contraction of "omnibus bar"; omnibus being "for all" in Latin). A bus bar is a large power conductor to which numerous connections are made. Another possible derivation is by analogy to a public-transport bus, which carries many passengers and stops at all bus stops along its route. Similarly, a computer bus carries many signals at once and exchanges them with all devices connected to it. Each...