1. Bridge is a network, usually consisting of four branches, connected so that an input signal can be applied between two opposite points and the output taken between the other two opposite points. When the component values are in a certain ratio, the voltage between the output points is zero, and the bridge is said to be balanced or set to null.
2. It is a circuit such as that described in (1) used for electrical measurements.
3. It is an audio or servo amplification system in which the load is driven from two outputs having opposite polarity, neither of which are at ground potential.
4. It is a communications path between or among two or more networks. This allows the subscribers in any network to obtain data from, or send data to, any other network, in effect creating a network of networks.
See also, Bridge Rectifier Circuit, Balanced Bridge