Glossary of Organ Terms

Adapted from A Young Person’s Guide to the Pipe Organ by Sandra Soderlund, www.agohq.org/guide/pages/index1.html

Action                          the parts of an organ that connect the keys with the pipes.

Reservoir                     an apparatus consisting of a wooden box and folded leather bellows that collects
                                    wind and delivers it to the wind chest, maintaining the proper wind pressure.

Blower                          an electric fan that provides wind for the pipes.

Celeste                        a rank of string pipes tuned slightly sharp to cause a gentle undulation in the tone
                                    when played with its companion rank.

Chamber                      a room housing the pipes of an organ, opening into the main room.

Choir                           a division of the organ, usually played from the lowest of three manual keyboards,
                                    often enclosed.

“Chorus” reeds            reed stops designed to be used in combinations with flues.

“Color” reeds               reed stops designed to be used as solo stops.

Combination action     a mechanical system allowing the organist to change several stops simultaneously,
                                    using buttons (pistons) or toe studs.

Console                       the control center of the organ, where the player plays.

Coupler                       a device that makes the pipes from one division sound on another keyboard than
                                    its own.

Crescendo pedal         a foot-operated lever that brings on stops and couplers gradually.

Cut-up                         the distance between the upper and lower lips of a flue pipe mouth; influences
                                    pipe tone color.

Diapason                     a flue pipe with basic organ tone.  Also called Principal.

Division                       a section of the organ, usually with its own keyboard and pipes.

Electric action             action that uses electricity to open and close the pipe valves.

Façade                        the visible front of the organ chamber or case.

Flue                             an organ pipe that makes sound by setting a column of air vibrating.

Flute                            a flue pipe of wide scale, made of wood or metal.

Great                           the main division of an organ, usually played from the lower of two or the middle of
                                    three manual keyboards.

Languid                       a disk of metal placed horizontally inside a flue pipe to channel the wind against
                                    the upper lip of the pipe mouth.

Manual                        a keyboard played with fingers.

Mechanical action       action that uses rods called “trackers” and other mechanical parts to connect the
                                    keys with the pipe valves.

Mixture                        a stop of more than one rank of pipes at various high pitches.

Mouth                          the hole cut in the body of a flue pipe; the wind passes through the gap between
                                     the languid and the lower edge, or lip, of the mouth and is thereby directed toward
                                     the upper lip, creating sound waves which are amplified by the body of the pipe.

Pedal                           a keyboard played with feet.

Pistons                        buttons and toe studs that change stops and couplers and may be set by the
                                    organist.

Rank                            a row of pipes of one tone color brought into play by a stop knob.

Reed                            an organ pipe that makes sound by the vibration of a reed against a hollow tube
                                    called a “shallot.”

Resonator                    the body of a reed pipe, which amplifies and modifies the sound of the reed itself.

Romantic                     refers to instruments and music of the later 19th and early 20th century or in that
                                    style.

Scale                           in organ pipes, the relationship of the diameter of a flue pipe to its length.

Shades/Shutters         the heavy wooden slats that enclose a swell box.

Shallot                         in a reed pipe, the hollow brass tube against which the tongue vibrates.

Specification               a list of the stops or ranks found in an organ.

Spotted metal             a combination of tin and lead used for metal pipes.

Stop                             the knob or tablet that brings a rank of pipes into play.

Stopped pipe               a flue pipe that is closed at the top with a cap or stopper, making it sound an octave
                                    lower than an open pipe of the same length.

String                           flue pipes of narrow scale, voiced to have many harmonics.

Swell                            a division of the organ enclosed in a box with shutters (shades) adjustable by the
                                    player.

Swell Box                     the enclosure built around a division to provide it with shades. Often used for Choir
                                    or other divisions in addition to Swell.

Swell Shoe                   a foot-operated lever that controls the opening and closing of the swell shades.

Toe Stud                      a large button near the pedal keyboard that operates a piston.

Tongue                         a thin strip of brass that vibrates against the shallot of a reed pipe, creating the
                                    sound waves of the pipe.

Tracker                        in mechanical-action organs, a rod that connects the key to the pipe valve.

Tremolo                       a device that creates a gentle oscillation of wind pressure, making the sound of the
                                    pipes waver in a manner similar to the “vibrato” of the human voice.

Wind Chest                  the box on which pipes stand, filled with wind (pressurized air.)