The pipe organ is a musical instrument commonly used in churches or cathedrals that produces sound by driving pressurized air (called wind) through pipes selected via a keyboard. Because each organ pipe produces a single pitch, the pipes are provided in sets called ranks, each of which has a common timbre and volume throughout the keyboard compass. Most organs have multiple ranks of pipes of differing timbre, pitch and loudness that the player can employ singly or in combination through the use of controls called stops. A pipe organ has one or more keyboards (called manuals) played by the hands, and a pedalboard played by the feet, each of which has its own group of stops. The organ's continuous supply of wind allows it to sustain notes for as long as the corresponding keys are depressed, unlike the piano and harpsichord whose sound begins to decay immediately after attack.
Contributions by Andrewa, MDCollins, and Cor anglais 16.