The xylophone (from the Greek words —xylon, "wood" + —phone, "sound, voice", meaning "wooden sound") is a musical instrument in the percussion family that consists of wooden bars struck by mallets. Each bar is an idiophone tuned to a pitch of a musical scale, whether pentatonic or heptatonic in the case of many African and Asian instruments, diatonic in many western children's instruments, or chromatic for orchestral use.