The organ (from Greek όργανον – organon, "organ, instrument, tool") is a keyboar instrument played using one or more manuals and a pedalboard. It uses wind moving through metal or wood pipes to produce sound, which remains constant while a key is depressed. Its sounds, which vary widely in timbre and volume, are divided according to ranks and controlled by the use of stops. The keyboard is not expressive and does not affect dynamics. Organs vary greatly in size, ranging from a cubic yard to a height reaching five floors , and are located primarily in churches, concert halls, and homes. The organ is one of the oldest musical instruments in the Western musical tradition, and carries a rich history connected with Christian liturgy and civic ceremony.