organ

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Music An instrument consisting of a number of pipes that sound tones when supplied with air and a keyboard that operates a mechanism controlling the flow of air to the pipes. Also called pipe organ.
2. n. Music Any one of various other instruments, such as the electronic organ, that resemble a pipe organ either in mechanism or sound.
3. n. Biology A differentiated part of an organism, such as an eye, wing, or leaf, that performs a specific function.
4. n. An instrument or agency dedicated to the performance of specified functions: The FBI is an organ of the Justice Department.
5. n. An instrument or a means of communication, especially a periodical issued by a political party, business firm, or other group.

Century Dictionary and Cyclopedia

1. n. An instrument or means; that which performs some office, duty, or function; that by which some action is performed or end accomplished.
2. n. A medium, instrument, or means of communication between one person or body of persons and another; a medium of conveying certain opinions: as, a secretary of state is the organ of communication between the government and a foreign power; an official gazette is the organ of a government; hence, specifically, a newspaper which serves as the mouthpiece of a particular party, faction, cause, denomination, or person: as, a Republican organ; a party organ.
3. n. In biology, one of the parts or members of an organized body, as an animal or a plant, which has some specific function, by means of which some vital activity is manifested or some vital process is carried on: as, the organs of digestion, circulation, respiration, reproduction, locomotion; the organ of vision or of hearing; the vocal organs.
4. n. The vocal organs collectively; the voice: now rare except in a somewhat technical or cant application with reference to the musical use of the voice.
5. n. In phrenology, any part of the brain supposed to have a particular office or function in determining the character of the individual, and to be indicated by one of the areas of cerebral surface recognized by phrenologists: as, the organ of acquisitiveness, of alimentiveness, of inhabitiveness, etc.
6. n. The largest, the most complicated, and the noblest of musical instruments, consisting of one or many sets of pipes sounded by means of compressed air, the whole instrument being under the control of a single player; a pipe-organ, as distinguished from a reed-organ. Historically, the principle of sounding a pipe pneumatically has been known from the earliest times. The combination of pipes or whistles into graduated series, so as to produce the tones of some sort of scale, appears in the primitive Pan's-pipe and in the Chinese cheng, both of which are blown by the breath, the latter being perhaps the actual prototype of the modern organ. Instruments of this general class seem to have been used in Europe from the first Christian centuries, having some apparatus for furnishing compressed air and a set of pipes the sounding of which was variously controlled. Soon after the tenth century great improvements were made, affecting every part of the mechanism. The process of mechanical development has been continuous ever since, and is still going on. The original impetus to this steady progress is due to the fact that the pipe-organ has been recognized ever since the fourth or fifth century as preëminently the church musical instrument. Until the sixteenth century no other instrument commanded the careful study of educated musicians. Its application to purely concert uses is comparatively recent. The modern pipe-organ consists essentially of three mechanical systems: the wind-supply, the compressed air used being technically called wind; the pipework, including the entire sound-producing apparatus; and the action, the mechanism by which the player controls the whole. The wind-supply includes two or more feeders, oblique bellows which are operated either by hand or by a water, gas, steam, or electric motor or engine; a storage-bellows, horizontal bellows into which the feeders open, and in which the air is kept at a uniform pressure by means of weights; wind-trunks, distributing the compressed air to the several parts of the instrument; and wind-chests, boxes directly under the pipes, in which are the valves for admitting the air to particular pipes or sets of pipes. Occasionally certain solo pipes are supplied with air from a special storage-bellows in which the tension is made greater by extra weights; such pipes are said to be on extra or heavy wind. The pipework includes a great variety of different kinds of pipes, made either of metal or of wood, arranged in sets called stops or registers, at least one pipe being usually provided in each set for each digital of the keyboard. In general, all pipes are either flue-pipes, which are either open at the upper end or plugged, or reed-pipes, the former producing tones through the impact of a stream of air upon the sharp edge or lip of a mouth in the side of the pipe, and the latter producing tones by the vibration of a tongue or reed placed over or in an orifice through which the air passes. (See pipe.) The pipes in a given set or stop are alike, except in size and pitch. The four principal qualities of tone produced are the true organ-tone, given by open metal flue-pipes of broad scale; the flute-tone, given by stopped wooden flue-pipes; the string-tone, given by open metal flue pipes of narrow scale; and the reed-tone, given by reed-pipes of various shape and material. A stop whose tones correspond exactly with the normal pitch of the digitals with which the several pipes are connected is called an eight-feet stop; one whose tones are uniformly an octave lower is called a sixteen-feet stop; while those whose tones are uniformly one or two octaves higher are called four-feet and two-feet stops respectively. Stops whose tones are different from the normal pitch of the digitals used, or from their upper or lower octaves, are called mutation-stops, in distinction from the above foundation-stops. Stops that have more than one pipe to the digital are called mixture-stops or mixtures. It is customary to group together several stops of different construction, tone-quality, and pitch upon a single wind-chest, and such a group of stops constitutes a partial organ. Usually from two to five such groups of stops or partial organs are introduced, such as the great organ, the chief and most sonorous of all; the swell-organ, so called because shut up in a tight box one side of which consists of shutters which may be opened or shut so as to let out or muffle the sound; the choir-organ, specially intended for accompanying either voices or other stops of the organ itself; the solo-organ, providing stops of very conspicuous power and individuality; and the pedal organ, including deep-toned stops played from a keyboard for the feet, and supplying the fundamental tones of the harmony. The number, order, power, and quality of the stops placed in these several partial organs vary widely. Each is complete in itself, having its own wind-chest and keyboard, so that it can be used independently of the others; but by means of couplers any pair may be played conjointly from a single keyboard. (See coupler.) The action includes one keyboard for each partial organ, a stop-knob for each stop, a knob or piston for each coupler, a swell-pedal, combination pedals, etc. Keyboards for the hands are called manuals, and those for the feet pedals, each being made up of the usual white and black digitals or keys. The manuals usually have a compass of nearly or about five octaves, beginning on the second C below middle C, while the pedals have about half this compass, beginning an octave lower. The manuals are placed above each other in a desk-like case; when there are two, the lower belongs to the great organ, and the upper to the swell-organ; when there are three, the lowest belongs to the choir-organ. The stop knobs, bearing the names of the stops, are placed on both sides of the manuals, and are grouped according to the partial organs to which they belong. When a stop is to be used, its knob is pulled forward, or “drawn.” Frequently combination pedals or pistons are provided, by which several knobs may be drawn or retired at once. Sometimes, also, a crescendo pedal is introduced, by which the entire resources of the instrument may be gradually called into action. The keyboards may be combined in various ways by means of couplers. The digitals of the keyboards are connected with the valves in the wind-chests by a complicated series of stickers, squares, rollers, trackers, etc., which are almost entirely made of wood. In large organs the friction of the key-action is so great that a pneumatic or electric action is employed, in which the digitals merely make connections so that compressed air or electricity may do the work. The stop-knobs are connected with the wind-chests by similar systems of levers, rods, squares, etc., which are also often pneumatically or electrically manipulated. When a digital on one of the keyboards is depressed, a valve is opened from the wind-chest belonging to that keyboard, admitting the compressed air to a groove or channel over which stand all the pipes belonging to the digital: only those pipes, however, are sounded that belong to the stops whose stop-knobs happen to be drawn. The opening and closing of the shutters of the swell-box is manipulated through a special swell-pedal. Various other mechanical accessories are often added, such as the tremulant, a device by which an oscillating tension is given to the air in one of the wind-trunks, the pedal-check, the bellows-signal, etc. The history of organ music until the sixteenth century was coincident with that of vocal music, for which it merely afforded a basis; but since that time it has had a remarkable independent development, particularly in the works of J. S. Bach. The organ has been much used in conjunction with choral music to enhance broad harmonic effects; and lately it has been also applied to the elaborate imitation of orchestral music. It remains the distinctively church instrument, although it is often found in concert-halls and in opera-houses. Formerly the instrument was often spoken of as a pair of organs, or simply organs.
7. n. One of the independent groups of stops of which a pipe-organ is made up; a partial organ, such as the great organ, the swell-organ, etc., described above.
8. n. A harmonium or reed-organ.
9. n. Some other musical instrument, as a pipe or harp.
10. n. A pipe-organ the action of which is manipulated with the help of electricity.
11. n. Same as choir-organ.
12. To furnish with organs; organize.
13. n. Same as origan.

Wiktionary

1. n. A largest part of an organism, composed of tissues that perform similar functions.
2. n. by extension A body of an organization dedicated to the performing of certain functions.
3. n. music A musical instrument that has multiple pipes which play when a key is pressed, or an electronic instrument designed to replicate such.
4. n. An official magazine, newsletter, or similar publication of an organization.
5. n. A species of cactus (Stenocereus thurberi)
6. n. slang The penis.
7. v. obsolete, transitive To supply with an organ or organs; to fit with organs.

GNU Webster's 1913

1. n. An instrument or medium by which some important action is performed, or an important end accomplished.
2. n. (Biol.) A natural part or structure in an animal or a plant, capable of performing some special action (termed its function), which is essential to the life or well-being of the whole.
3. n. A component part performing an essential office in the working of any complex machine.
4. n. A medium of communication between one person or body and another; A newsletter distributed within an organization is often called its house organ.
5. n. (Mus.) A wind instrument containing numerous pipes of various dimensions and kinds, which are filled with wind from a bellows, and played upon by means of keys similar to those of a piano, and sometimes by foot keys or pedals; -- formerly used in the plural, each pipe being considered an organ.
6. v. obsolete To supply with an organ or organs; to fit with organs; to organize.

WordNet 3.0

1. n. a fully differentiated structural and functional unit in an animal that is specialized for some particular function
2. n. wind instrument whose sound is produced by means of pipes arranged in sets supplied with air from a bellows and controlled from a large complex musical keyboard
3. n. a free-reed instrument in which air is forced through the reeds by bellows
4. n. a government agency or instrument devoted to the performance of some specific function
5. n. (music) an electronic simulation of a pipe organ
6. n. a periodical that is published by a special interest group