Dictionary.net

A network topology in which all nodes areconnected to a single wire or set of wires (the bus). Busnetworks typically use CSMA/CD techniques to determine whichnode should transmit data at any given time.Some networks are implemented as a bus, e.g. Ethernet -a one-bit bus operating at 10, 100, 1000 or 10,000 megabitsper second. Originally Ethernet was a physical layer busconsisting of a wire (with terminators at each end) to whicheach node was attached. Switched Ethernet, while no longerphysically a bus still acts as one at the logical layers.