An electrical bus (sometimes spelled buss) is a physical electrical interface where many devices share the same electric connection. This allows signals to be transferred between devices (allowing information or power to be shared). A bus often takes the form of an array of wires that terminate at a connector which allows a device to be plugged onto the bus.
Buses are used for connecting components of a computer: a common example is the PCI bus in PCss. See computer bus.
Buses are used for distribution of electrical power to components of a system. The (usually) thick connectors used are called bus-bars. In an electrical laboratory, for example, a bare bus-bar will sometimes line the wall, to be used by the engineers and technicians for its high electrical current carrying capacity, which allows a convenient approximation to zero voltage, or ground in the US, and earth in the UK.