This glossary has been produced to help those interested in organs but not familiar with the organ terminology.  If you have any queries or words you’ve heard before but find that they aren’t listed below, then please send us an email and let us know and we’ll add it to our list.

ACTION:  An action may be mechanical, pneumatic, or electrical (or some combination of these, such as electro-pneumatic action). An organ contains two actions, or systems of moving parts. When a key is depressed, the key action admits wind into a pipe. The stop action allows the organist to control which ranks are engaged.    An electrical connection which, when charged, it magnetizes a piece of metal. This circuit is involved in the mechanism which opens the valves to allow pipes to speak
Sloane Street, Holy Trinity - zinc basses(2)BASSES: The largest pipes in the organ.  The bottom notes of a given stop.
Detall_orgue_7BELLOWS: Before electricity, bellows were used to supply air. It was made of two wedge shaped pieces of wood joined by an expandable, fan-like piece of leather. Closing the bellows forced air into the Reservoir.
BLOWER: In organs of the twentieth century, a rotary fan for producing organ wind, usually driven by an electric motor. The wind supplied is stored in one or more regulators to maintain a constant pressure in the windchests until the action allows it to flow into the pipes
Great Spitz Flöte 8ft (1)BODY: The upper part of a flue pipe, measured upward from the mouth to the end of the pipe.  A pipe body may be either open, closed or partially closed.
Cheltenham College 32 ft reed Pipes and boots 6BOOT: The lower part of a reed pipe, containing the sound-producing mechanism: shallot and tongue.
Exeter Cathedral - upper Swell boxBOXES:  Usually refers to a swell box.  See Swell shutters.
Edington Priory - frame from above (1)BUILDING FRAME: The structure upon which the organ components are set.  Usually constructed of wood, jointed and bolted together.
Edington Priory (1)CASE:  An enclosure for chests and pipes, usually free-standing.  Often decorated and an important part of the acoustical and visual aspect of many organs.
Edington Priory - Vox Celeste pipe bodyCELESTE: A rank of pipes similar in scale and voicing to another rank on the same chest, intentionally tuned either sharp or flat in comparison to the unison rank.  The effect when the two ranks are played together is a gentle undulation in the pitch.
CIRCUIT: An electrical connection, when charged, magnetizes a piece of metal. The circuit is part of the mechanism which opens the valves to allow pipes to speak.
   CHEST: See Windchest
ChoirCHOIR: 1. Usually the lowest manual of the organ console.  A corruption of “chair”, referring to a division placed behind the organ bench.  Equivalent to the German “Rückpositiv”  2. An enclosed division containing stops useful for accompanying a choir of voices.
COMPASS:  The range of a keyboard, referring to the normal pitch of the keys themselves, not of the actual sounding pitch of a specific stop.  Thus, in normal usage, “compass” refers to the keys, “range” to the pitches played by those keys.
CONSOLE: The console consists of a cabinet containing the manual and pedal keyboards and the stop control. The console is either built into the organ case or detached from it and there is a bench for the organist to sit.  Parts of the organ action are found in the cabinet.
Pedal couplerCOUPLER:  A coupler allows the stops of one division to be played from the keyboard of another division.
RFHDETACHED CONSOLE: A console separated from the rest of the organ, rather than built into the organ case.
DIVISION: A section of the pipes and related windchests of an organ, usually consisting of several ranks of pipes on one chest, meant to be used in various combinations and controlled by a specific keyboard.  A “floating” division has no home keyboard; it may be coupled to any one of several keyboards and played from any one or all of them.
reassembly of a drawstop actionDRAWSTOP ACTION: The mechanism that moves the slider.  May be mechanical, pneumatic, electro-pneumatic or direct electric.
ELECTRO-MECHANICAL ACTION: A System of windchest and connections to the key that permits direct connection from keyboard to open a pallet through an electromagnet.
ELECTRO-PNEUMATIC ACTION: In an electro-pneumatic key action the key operates a switch, which in turn activates a magnet.  Each key has a pair of contacts and a wiper. At the action a lever magnet operates the first stage of the action.In an electro-pneumatic drawstop action the stop knob operates a switch, which in turn activates a magnet.  Each stop knob has a pair of contacts and a wiper. At the action a chest magnet operates the first stage of the action.
FLUE/FLUE PIPE: 1. The opening for wind between the lower lip and the languid.  2 A pipe which produces its sound when wind passes through the flue and strikes the upper lip.
Solo Harmonic FluteFLUTE:  1. The term identifies a smooth-toned stop of low harmonic development produced by either stopped, half stopped or open flue pipes.  2.  In particular traditions, especially French, Flûte identifies a wide-scaled open flue with a narrow mouth and high cut-up.  Flute stops (in either sense) may appear at any pitch level.
Temple Church - boots for Cor Anglaise 1FOOT/PIPE FOOT: The bottom section of a flue pipe.  In metal pipes usually in the shape of an inverted cone, open at the bottom (the toehole) and almost completely closed at the top by the languid.  In wooden pipes the foot is usually a square or rectangular extension of the body with a cylindrical extension at the end of which is the toe.
   FRAME: see building frame
DSC00943smallFREE STANDING: This describes an organ which is entirely self-contained in its own case. It is supported on its own pedestal. Its case is free to resonate on all sides and on top.
Great pipeworkGREAT: The Great is the primary manual division of an organ.  Characterized by a principal chorus that establishes the primary characteristics of the sound of an individual instrument.
KEY ACTION:  This is the mechanism the keyboard uses to control the pipe speech.  It does this by controlling the air flow to the pipes.
Charterhouse PedalboardKICKBOARD: The horizontal panel above the pedalboard, between the pedals and the lowest manual.  Expression pedals, coupler controls and toe studs may be located on or set into the kickboard.
Ripon Cathedral - languids being solderedLANGUID: A horizontal plate that separates the body from the foot of a flue pipe.
MANUALS: Manuals or keyboards, control their own set of pipes.  Manual keyboards resemble those of a piano. Having more than one Manual makes possible quick changes in registration (by moving from one Manual to another) or solo effects with accompaniment (by playing on two Manuals at once).
 mechanical stop action combination machine (5)MECHANICAL ACTION:  The system for connecting the console to the rest of the organ.  A system for conducting motion from keys and stop controls to the windchest through the use of mechanical connections using stickers, trackers, and squares.  This system is also called ‘Tracker Action’.
Kings - Pedal mixture (5)MIXTURE:  Organ stops consisting of more than one rank of pipes.
Sloane Street - mouths of Great Double Open pipesMOUTH: The opening in the side of a flue pipe, where the foot joins the body.
Sloane St - removable palletsPALLET: A part under the pipe in the windchest, used to open and close holes that admits air into the pipe, causing it to speak when the key is depressed.

1.In a pallet and slider chest, a small piece of wood, fixed in position and free to move to the other.    2.In electro-pneumatic chests, a small disc of felt or similar          material.   3.A padded disc attached to the armature of a magnet in an          electro-mechanical windchest.

Sloane Square, Holy Trinity - Solo sliders and solenoidsPALLET AND SLIDER CHEST:  A windchest in which pallets, controlled by keys, and sliders, controlled by stops, admit wind to pipes.  The oldest type of windchest in common use.
PALLET BOX: The lower portion of a pallet and slider chest, from which wind is admitted to individual key channels by the action of pallets.
Sloane street - being assembledPASSAGEBOARD:  Access way within the organ.
PEDALBOARD: A special keyboard in the console designed to be played by the feet. Every organ has a Pedal, as it is needed to play the bass parts in organ literature.
PIPE RACK: A horizontal board located above the pipe chest, solidly fastened to the chest or to an adjacent vertical surface, and in line with a given set of pipes, used to support the larger pipes by means of ties or hooks. It also prevents accidental overturning of pipes during tuning and helps keep reed pipes in tune by reducing their tendency to move from vibration.
PIPES: These produce the sound and are constructed of either wood or metal. Each pipe produces a single tone, and it takes a series of them, one per key, to play the entire range of the keyboard. There are two classes of pipes; Reed pipes, which have a vibrating tongue producing the tone and a resonator to modify its quality; Flue pipes, with no moving parts except the air, like a whistle.
Royal Festival Hall - Positive TrumpetPOSITIF/POSITIV: A secondary manual division, unenclosed, usually containing a principal chorus that is of smaller scale and based on a higher pitch than that of the primary manual chorus (Great).
 Pedal PrincipalPRINCIPAL: The  primary tone color of the organ, produced by open flue pipes of moderate scale.  Voicing of principals varies in instruments from different places and different periods.  In different instruments, stops of principal tone color may be called Diapason, Principale, or Prizipal, or they may be indentified only with a pitch designation, such as Fifteenth, Octave or Decimanona.
Exeter Cathedral - racks RACKBOARDS: A method of supporting organ pipes.  A horizontal board with holes set above the upperboard.  Placing the pipes in the rackboard is called ‘racking in’.
Edington Priory - racking in Swell Flue (1)RANK: A set of pipes of similar construction, arranged on a windchest so that there is one pipe for each note of the keyboard which sounds the pipes.
Cheltenham College - 32ft reed pipesREED:  1. A pipe that produces its sound through the vibration of a tongue against a shallot.  2. In some uses, an alternate name for either tongue or shallot.
RESERVOIR (BELLOWS): A mechanism for both storing organ wind and controlling its pressure, located between the blower and the windchest.
Hakadal - rollerboard (1)   ROLLER: A mechanism in an organ with mechanical action for transferring motion from the key to a pallet located above and to the side of the end of the key.  Rollers are affixed to a “roller board,” typically a horizontal board, with its face parallel to the front of the keys.
SCALE:  The relationship between the diameter and length of the resonator of a pipe.
 shallots  SHALLOT: A brass tube located in the boot of a reed pipe, against which the tongue vibrates to produce a sound.
sliderSLIDER: A piece of wood or synthetic material with holes that align with those in both the topboard and the toeboard of a slider and pallet chest.  The slider is movable and in one postion closes off the wind to the pipes located above it.
STOP:   Each stop usually controls one rank of pipes, although mixtures and undulating stops (such as the Voix Céleste) control multiple ranks.  In unit organs, a rank of pipes may be activated in whole or in part by more than one stop control.  Also called “Stopknob” or “Stopkey”.
London, Temple Church - stop jambsSTOP KNOB:  The control allows wind to flow into the selected rank. The organist activates this by pulling (or drawing) the knob towards himself. This is the origin of the idiom “to pull out all the stops”. Stop Knobs are labelled with a name, such as Principal, and a number, such as 4′. The name describes the kind of sound and the number tells the pitch range.
Exeter Cathedral - upper Swell boxSWELL BOX: A division whose pipes are enclosed in a case or chamber fitted with shutters that can be opened or closed from the console using a foot pedal.
OLYMPUS DIGITAL CAMERASWELL PEDAL: A console control operated by the foot that opens or closes a set of shutters (see shades) placed across the opening of either a case or a chamber which contains one or more divisions of pipes.
SWELL SHUTTERS:  Louvered panels that can be opened or closed to allow varying degrees of enclosure of the pipes of a given division.  Also called a “Swell box”.
Colchester - Viole d'Orchestre (6)TOE/TOEHOLE:  1. The lower end of the foot of either a flue or reed pipe, and the part of the pipe that is in contact with the chest.  The toe is usually made of lead, even in wooden pipes; the size of the toehole regulates the amount of wind that can enter the pipe.  2. Toehole: the hole in the topboard of a windchest that admits wind to a pipe.
Pedal Trombone tongues being fitted  TONGUE:  A thin strip of brass that vibrates to produce the sound in a reed pipe.
Union Chapel, Islington - repairing trackersTRACKER: 1. A thin strip of wood (or metal) that carries motion of the key to the windchest by a pulling motion in an instrument that is built with a mechanical action.  Often used incorrectly to describe a sticker.  2. An organ that uses mechanical action, which is also called “tracker action”.
 trackerTRACKER ACTION: Another name for mechanical action.  Connection is achieved through a series of rods called trackers. When the organist depresses a key, the corresponding tracker moves, allowing wind to enter the pipes.
West Abb - with some treble pipes in place8-9-8TREBLES: The smallest pipes in an organ.  The highest notes of a given stop.
Temple Church - wind trunkTRUNKS:  Ducts that convey wind through an organ,  Can be either of wood or metal.
Duncan Bennett tuning TUNING: Tuning is the process of adjusting each pipe in the organ to the correct pitch so that they all sound in tune with each other. How the pitch of each pipe is adjusted depends on the type and construction of that pipe. The pitch is affected by temperature of the air in and around the pipes and tuning fluctuates with temperature changes so it must be re-done periodically so the organ sounds its best.
 UPPER BOARD: The top layer of a windchest upon which pipes stand.
setting the c's for voicing VOICING: The procedure of adjusting the various parts of a pipe to produce the desired tone.
WIND: The pressurised air which makes the organ pipes sound.
WINDCHEST: A mechanism for admitting wind to selected pipes.  The ‘chest’ contains wind under pressure.
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Adapted from a glossary by James H Cook and Wikipedia.