A keyboard instrument is a musical instrument that is played by depressing keys on a keyboard with the fingers. This diverse category includes pianos, organs, harpsichords, clavichords, accordions, carillons, and some electronic musical instruments. The sound is produced in various ways, including by striking wires, plucking wires, allowing an air flow, striking a bell, and completing an electronic circuit.
Some percussion instruments, including the xylophone, glockenspiel, marimba and vibraphone, have sound elements (such as pieces of metal or wood or a bell) that are arranged in a keyboard layout. However, they are usually played by striking each sound element with a small mallet rather than by pressing a key.