[music] A sound board, or soundboard, is the surface of a string instrument that the strings vibrate against, usually via some sort of bridge. The resonant properties of the sound board and the interior of the instrument greatly increase loudness over the string alone. The sound board operates by the principle of forced vibration; the board...
• (n.) A sounding-board.
A device that synthesizes tones and shares interrupts with printer ports. 
Sound'-board` noun A sounding- board. « To many a row of pipes the sound-board breathes.» Milton.