The xylophone (from the Greek wors ξύλον - xylon, "wood" + φωνή - phone, "voice", meaning "wooden sound") is a musical instrument in the percussion family which probably originated in Indonesia. It consists of wooden bars of various lengths that are struck by plastic, wooden, or rubber mallets. Each bar is tuned to a specific pitch of the musical scale. Xylophone can refer to western style concert xylophones or to one of the many wooden mallet percussion instruments found around the world. Xylophones are tuned to different scale systems depending on their origin, including pentatonic, heptatonic, diatonic, or chromatic. The arrangement of the bars is generally from low (longer bars) to high (shorter bars).