A set of keys, as on a computer terminal, word processor, typewriter, or piano. Music A piano. Music Any of various instruments, played by means of a set of pianolike keys, often connected to a synthesizer or amplifier. To set (copy) by means of a keyed typesetting machine: keyboard a manuscript. To enter (text or data) into a computer by means of a keyboard. Music To play (a composition) on a piano or keyboard.