On traditional string instruments, such as the violin, viola and cello, the bridge is the arch-shaped piece of wood that holds the strings up above the fingerboard, creating tension in the strings and relaying the vibrations of the strings into the sound box where they are amplified. In order for the bridge to properly transfer vibrations into the sound box, it must be placed in the correct position on the front of the instrument so that it's 'feet' rest above the bass bar and sound post inside the instrument.
Bridge is also the name of a composer, Frank Bridge.
Electronics and computers
A Wheatstone bridge is a diamond-shaped arrangement of resistors, useful in comparing resistances to high standards of accuracy. If alternating currents are applied and a device used to measure alternating currents is substituted, a similarly arranged bridge may be used to proportionally compare capacitors or inductors.
A bridge rectifier is a diamond-shaped configuration of diodes used to convert alternating current to direct current.
A bridge or bridge loan is the financing for a construction project that is replaced by (paid off with the proceeds of) a mortgage on the property once it is built. It is also used in the financing of new or expanding corporations to keep the company operating between rounds of private placement stock sales (venture capital) or pending an initial public offering (IPO). A bridge loan may also be a short-term loan to cover a gap in time between two long-term loans.