key

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A notched and grooved, usually metal implement that is turned to open or close a lock.
2. n. A similar device used for opening or winding: the key of a clock; a can that has a key attached.
3. n. A means of access, control, or possession.
4. n. A vital, crucial element.
5. n. A set of answers to a test.
6. n. A table, gloss, or cipher for decoding or interpreting.
7. n. A device, such as a wedge or pin, inserted to lock together mechanical or structural parts.
8. n. Architecture The keystone in the crown of an arch.
9. n. A button or lever that is depressed to operate a machine.
10. n. A button that is depressed to cause a corresponding character or function to be typed or executed by a typewriter or to be accepted as input by a computer.
11. n. Music A button or lever that is depressed with the finger to produce or modulate the sound of an instrument, such as a clarinet or piano.
12. n. Music A tonal system consisting of seven tones in fixed relationship to a tonic, having a characteristic key signature and being the structural foundation of the bulk of Western music; tonality.
13. n. Music The principal tonality of a work: an etude in the key of E.
14. n. The pitch of a voice or other sound.
15. n. A characteristic tone or level of intensity, as of a speech or sales campaign. Often used in combination: high-key; low-key.
16. n. Botany A samara.
17. n. An outline of the distinguishing characteristics of a group of organisms, used as a guide in taxonomic identification.
18. n. Basketball An area at each end of the court between the base line and the foul line and including the jump-ball circle at the foul line: a jump shot from the top of the key.
19. adj. Of crucial importance; significant: key decisions; the key element of the thesis.
20. v. To lock with or as if with a key.
21. v. Architecture To furnish (an arch) with a keystone.
22. v. Music To regulate the pitch of.
23. v. To bring into harmony; adjust or adapt.
24. v. To supply an explanatory key for.
25. v. To operate (a device), as for typesetting, by means of a keyboard.
26. v. To enter (data) into a computer by means of a keyboard.
27. v. To identify (a biological specimen).
28. v. To vandalize or mar by scratching with a key: Vandals keyed the cars left in the parking garage.
29. v. To pay close attention; focus: improved service by keying on customer complaints; keyed in on the main points of the lecture.
30. v. Sports To watch or cover an opposing player closely in an effort to limit the player's effectiveness. Used with on: "[She] still carries the burden of scoring ... even though opponents key on her throughout every game” ( Josh Barr).
31. key up To make intense, excited, or nervous.
32. idiom. in key In consonance with other factors.
33. idiom. out of key Not in consonance with other factors.
34. n. A low offshore island or reef, especially in the Gulf of Mexico; a cay.
35. n. Slang A kilogram of marijuana, cocaine, or heroin.

Century Dictionary and Cyclopedia

1. n. An instrument for fastening or opening a lock, fitted to its wards, and adapted, on being inserted and turned or pushed in the keyhole, to push a bolt one way or the other, or to raise a catch or latch; in certain complicated locks, a portable appliance which on being inserted in the proper place in the lock lifts tumblers or in some other way allows the bolt to be shot without itself exercising force upon it.
2. n. Hence Something regarded as analogous to a key, in being a means of opening or making clear what is closed or obscure; especially, that by means of which (often by means of which alone) some difficulty can be overcome, some obstacle removed, some end attained, something unintelligible explained, etc: as, the key to knowledge; Gibraltar is the key to the Mediterranean; a key to the solution of an algebraic problem; a key to an algebra or arithmetic (a book giving the solution of mathematical problems proposed as exercises in such text-books); the key to a cipher.
3. n. In mech.: A hand-tool for controlling a valve, moving a nut, etc., which is independent of the part to be moved. In this sense a spanner, wrenc'h, bedstead-wrench, etc., are keys.
4. n. Any device for wedging up or locking together different parts, or for jamming or binding them to prevent vibration or slipping. Such are: the wedge or cotter driven between the hub of a wheel and its shaft to bind the two together; a wedge in a chain to prevent slipping; a wedge put in a split tenon to cause it to spread when driven into a mortise.
5. n. A bolt which secures the cap-square to the cheek of a gun-carriage. See cut under guncarriage.
6. n. In masonry, the central stone of an arch or vault, usually the uppermost stone; the keystone (although in a true arch no one of the voussoirs is more important to the stability of the structure than any other). See cut under arch, In carpentry: A piece inserted in the back of a board to prevent warping. The last board in a series of floor-boards, tapering in shape, and serving when driven home to hold the others in place. The roughing on the under side of a veneer, designed to assist it in holding the glue.
7. n. In bookbinding, one of a series of small tools used by the sewer of a book to keep the bands in place when the sections of the book are in a sewing-bench. They are made of metal or hard wood, shaped like a yoke, or the letter U, and of the size 1 by 3 inches.
8. n. A joint to assist in supporting a train of rods and the tools in a tube-well.
9. n. A wrench or lever for tuning stringed instruments of fixed intonation, like the pianoforte and the harp; a tuning-wrench or tuning-hammer. It consists of a metal head hollowed so as to fit closely over the tuning-pins, and a handle, usually long enough to give considerable leverage.
10. n. The surplus mortar or plaster that passes between the laths, and serves to hold the plastering in position.
11. n. A hollow cut in the back of a tile or terra-cotta ornament, or on a wall, to hold mortar or cement.
12. n. In musical instruments: In instruments especially of the wood wind group, a lever and valve operated by the player's finger, and designed either to open or to close a hole or vent in the side of the tube, so as to alter the pitch of the tone by altering the length of the vibrating air-column within. While in the simpler varieties of the flute, the oboe, the clarinet, etc., such holes are controlled by the fingers directly, in more complex varieties the number of holes is so great, and their position and size are so inconvenient, that this supplementary mechanism is a necessity. A complete system of keys was first elaborated for the flute by Theobald Boehm in 1832, and has since been applied to the oboe, the clarinet, and to some extent to the bssoon, with a decided gain in ease of manipulation, length and fullness of compass, and sonorousness of tone. Partial systems of keys are also found in the English horn, the basset-horn, etc. Holes and keys have been used in various brass wind-instruments, notably in the bugle and the saxophone, though as a rule they are less used than valves. (See valve.) See cuts under flute, clarinet, oboe, etc.
13. n. In instruments with a keyboard, like the organ and the pianoforte, one of the levers which are depressed in the act of playing. When operated by the finger, it is more exactly termed a digital or (rarely) a manual; when operated by the foot, a pedal. In the pianoforte each key or digital is connected with a series of levers, by which a hammer may be thrown against the string or strings belonging to that key, at the same time lifting from the strings the damper that prevents their vibration. When the key is released, the damper falls and stops the vibration. The duration, the force, and to some extent the quality of the tone depend upon the way in which the finger depresses the key. (See touch.) In the harpsichord each key, with its levers, slips a leather or quill plectrum past the string, so as to snap or twang it. In the clavichord each key pressesa metal tangent against the string, so as to drive it into vibration. In chimes of bells rung from a keyboard, each key throws a hammer against one of the bells. In the pipe-organ each key, whether a digital or a pedal, is connected with a series of levers, by which a valve is opened to admit the compressed air from the bellows into a particular groove or channel, over which stand all the pipes belonging to that key. The number of pipes actually sounded depends upon the number of stops drawn. (See cut under organ.) In the harmonium and reed-organ each key, with its levers, opens a valve, by which either an outward or an inward current of air is set up through the groove or channel with which are connected all the reeds belonging to that key. The number of reeds sounded depends upon the number of stops drawn. (See cut under reed-organ.) Keys in this sense are also (unfortunately) called notes. They are arranged according to an arbitrary plan,somebeing colored white and some black, and they are named by letters, etc., for which see keyboard.
14. n. A part pressed by the finger to control the action of a typewriter or other similar machine, in the manner of a musical keyed instrument.
15. n. Any one of the various forms of circuitcloser used in electrical experiments and in the practical applications of electricity. See telegraph.
16. n. In music: In musical theory, the sum of relations, melodic and harmonic, which exist between the tones of an ideal scale, major or minor, and in which its unity and Individuality are contained; tonality. Thus, a proper sense of these relations is called a proper sense of key, and a due observance of them puts a performance in key. For the difference between major and minor keys in this sense, see mode.
17. n. In musical theory and notation, the tonality centering in a given tone, or the several tones taken collectively, of a given scale, major or minor. The given tone, or the first tone of the given scale, is called the key-note, keytone, or tonic; and the key is named by the name of this tone. A scale is simply an arrangement of the tones of a key in their melodic order. In modern music, and in vocal music generally, all major keys are intended to be precisely similar to one another, except in pitch, and all minor keys likewise similar to one another. But in the systems of tuning instruments of fixed intonation before the middle of the eighteenth century, certain keys were favored and others slighted; so that some keys were very useful, and some practically useless. It is said that this difference, which was originally incidental to the imperfect plan of the keyboard, and which was to have been obliterated by the introduction of the equal temperament, is to some extent unavoidable, certain keys having a peculiar quality per se; but these differences appear, on close analysis, to be relative or accidental rather than essential. (See temperament.) The keyboard of the organ and the pianoforte, however, is so planned as to make a decided mechanical difference between keys or scales based on different digitals. For example, the major key or scale of the digital culled C requires the use of only white digitals, or naturals; hence it is called (unfortunately) the natural key. Other keys or scales require the use of one or more black digitals, which are called either sharps or flats; hence they are called the keys of one, two, three, or more sharps or flats, as the case may be. The keys of one or more sharps are called collectively the sharp keys; those of one or more flats, the flat keys. Practically, keys of more than six sharps or flats are rarely mentioned. (See circle of keys, under circle.) When these keys are represented by the staff-notation, the black digitals are indicated by marks ♮ or ♭ prefixed to certain of the notes. But since the key in which a piece is to be performed is the same either throughout, or at least for extended passages, these sharps or flats are customarily grouped into a key-signature at the begiuning of the piece or passage, and the effect of this signature is understood to continue until contradicted by further signs: thus—
18. n. (The crosses mark the degree belonging to the key-note.) The sharps and the flats in such signatures are counted from left to right; in sharp signatures the position of the key-note is always one degree above the last sharp, while in flat signatures it is always on the same degree with the last flat but one. This provides a rule for finding the keynote from each signature except those of the keys of C and of F. The key-notes of the sharp keys, taken in direct order, are distant from one another either by a fifth upward or a fourth downward, as are the key-notes of the fiat keys, taken in inverse order. These signatures are also used for minor keys, the key-notes of such keys being iu each case two degrees below the key-notes as given for major keys. The major and minor keys that use the same signature are termed relatives of each other. See relative. (See circle of keys, under circle.) The entire system of keys as described above is conditioned upon the keyboard of the organ and the pianoforte, and therefore is essentially arbitrary. It has no basis in the phenomena of sound or the necessities of music as an art. Its complexity is due historically to the iuadequate medieval theory of music, and secondarily to the arbitrary instrumental mechanism and the notation that grew out of that theory. Of the many attempts to improve or replace the system, the tonic sol-fa notation has been the most successful. See notation, and tonic sol-fa (under tonic).
19. n. In musical notation, a sign at the head of a staff indicating the key as above defined.
20. n. Scale of intensity; degree of force; pitch; elevation.
21. n. A dry winged fruit like that of maple, ash, elm, etc.; a samara. See cut under Acer.
22. n. A rudder; a helm.
23. n. A key (tonality) which on the keyboard involves the use of one or more black or chromatic keys (digitals), and on the staff necessitates a signature of one or more sharps or flats.
24. n. The major key (tonality) of C: so called because on the keyboard it involves the use of only white digitals, or naturals.
25. To fasten with a key, or with a wedge-shaped piece of wood or metal; fasten or secure firmly.
26. To regulate the tone of by the use of a key, or to set to a key or pitch in any way, as a musical instrument: as, to key up a violin.
27. n. A wharf. See quay.
28. n. A low island near the coast: used especially on the coasts of regions where Spanish is or formerly was spoken: as, the Florida keys.
29. n. See Keys.
30. n. In printing, the circular ratchet that closes or uncloses patent, quoins of iron.
31. n. A wooden pin for fastening hides together while they are being limed.

Wiktionary

1. n. One of a string of small islands.
2. n. An object designed to open and close a lock.
3. n. An object designed to fit between two other objects (such as a shaft and a wheel) in a mechanism and maintain their relative orientation.
4. n. A crucial step or requirement.
5. n. A guide explaining the symbols or terminology of a map or chart; a legend.
6. n. A guide to the correct answers of a worksheet or test.
7. n. computing One of several small, usually square buttons on a typewriter or computer keyboard, mostly corresponding to text characters.
8. n. music One of a number of rectangular moving parts on a piano or musical keyboard, each causing a particular sound or note to be produced.
9. n. music One of various levers on a musical instrument used to select notes, such as a lever opening a hole on a woodwind.
10. n. music A hierarchical scale of musical notes on which a composition is based
11. n. historical A manual electrical switching device primarily used for the transmission of Morse code.
12. n. cryptography A piece of information (e.g. a passphrase) used to encode or decode a message or messages.
13. n. computing In a relational database, a field used as an index into another table (not necessarily unique).
14. n. computing A value that uniquely identifies an entry in an associative array.
15. n. basketball The free-throw lane together with the circle surrounding the free-throw line, the free-throw lane having formerly been narrower, giving the area the shape of a skeleton key hole.
16. n. biology A series of logically organized groups of discriminating information which aims to allow the user to correctly identify a taxon.
17. n. slang kilogram
18. adj. Indispensable, supremely important.
19. adj. Important, salient.
20. v. To fit (a lock) with a key.
21. v. To fit (pieces of a mechanical assembly) with a key to maintain the orientation between them.
22. v. To mark or indicate with a symbol indicating membership in a class.
23. v. To depress (a telegraph key).
24. v. radio To operate (the transmitter switch of a two-way radio).
25. v. computing (more usually to key in) To enter (information) by typing on a keyboard or keypad.
26. v. colloquial To vandalize (a car, etc.) by scratching with an implement such as a key.
27. v. To link (as one might do with a key or legend).
28. v. intransitive (biology, chiefly taxonomy) To be identified as a certain taxon when using a key.

GNU Webster's 1913

1. n. An instrument by means of which the bolt of a lock is shot or drawn; usually, a removable metal instrument fitted to the mechanism of a particular lock and operated by turning in its place.
2. n. A small device which is inserted into a mechanism and turned like a key to fasten, adjust, or wind it
3. n. One of a set of small movable parts on an instrument or machine which, by being depressed, serves as the means of operating it; the complete set of keys is usually called the keyboard; The keys may operate parts of the instrument by a mechanical action, as on a piano, or by closing an electrical circuit, as on a computer keyboard. See also senses 12 and 13.
4. n. A position or condition which affords entrance, control, pr possession, etc.. that which serves to unlock, open, discover, or solve something unknown or difficult; Similarly, see also senses 14 and 15.
5. n. That part of a mechanism which serves to lock up, make fast, or adjust to position.
6. n. A piece of wood used as a wedge.
7. n. The last board of a floor when laid down.
8. n. A keystone.
9. n. That part of the plastering which is forced through between the laths and holds the rest in place.
10. n. A wedge to unite two or more pieces, or adjust their relative position; a cotter; a forelock.
11. n. A bar, pin or wedge, to secure a crank, pulley, coupling, etc., upon a shaft, and prevent relative turning; sometimes holding by friction alone, but more frequently by its resistance to shearing, being usually embedded partly in the shaft and partly in the crank, pulley, etc.
12. n. (Bot.) An indehiscent, one-seeded fruit furnished with a wing, as the fruit of the ash and maple; a samara; -- called also key fruit.
13. n. A family of tones whose regular members are called diatonic tones, and named key tone (or tonic) or one (or eight), mediant or three, dominant or five, subdominant or four, submediant or six, supertonic or two, and subtonic or seven. Chromatic tones are temporary members of a key, under such names as “ sharp four,” “flat seven,” etc. Scales and tunes of every variety are made from the tones of a key.
14. n. The fundamental tone of a movement to which its modulations are referred, and with which it generally begins and ends; keynote.
15. n. Fig: The general pitch or tone of a sentence or utterance.
16. n. (Teleg.) A metallic lever by which the circuit of the sending or transmitting part of a station equipment may be easily and rapidly opened and closed.
17. n. any device for closing or opening an electric circuit, especially as part of a keyboard, as that used at a computer terminal or teletype terminal.
18. n. (Biol.) A simplified version or analysis which accompanies something as a clue to its explanation, a book or table containing the solutions to problems, ciphers, allegories, or the like a table or synopsis of conspicuous distinguishing characters of members of a taxonomic group.
19. n. (Computers) A word or other combination of symbols which serves as an index identifying and pointing to a particular record, file, or location which can be retrieved and displayed by a computer program. When the key is a word, it is also called a keyword.
20. v. To fasten or secure firmly; to fasten or tighten with keys or wedges.
21. v. (Computers) To enter (text, data) using keys, especially those on a keyboard; to keyboard.
22. v. To adjust so as to be maximally effective in a particular situation; -- of actions, plans, or speech.
23. v. To furnish with a key or keys.
24. adj. Essential; most important.

WordNet 3.0

1. n. a generic term for any device whose possession entitles the holder to a means of access
2. v. harmonize with or adjust to
3. n. (basketball) a space (including the foul line) in front of the basket at each end of a basketball court; usually painted a different color from the rest of the court
4. n. the central building block at the top of an arch or vault
5. n. a kilogram of a narcotic drug
6. n. a lever (as in a keyboard) that actuates a mechanism when depressed
7. n. pitch of the voice
8. v. vandalize a car by scratching the sides with a key
9. v. regulate the musical pitch of
10. v. provide with a key
11. v. identify as in botany or biology, for example
12. n. United States lawyer and poet who wrote a poem after witnessing the British attack on Baltimore during the War of 1812; the poem was later set to music and entitled `The Star-Spangled Banner' (1779-1843)
13. n. metal device shaped in such a way that when it is inserted into the appropriate lock the lock's mechanism can be rotated
14. n. any of 24 major or minor diatonic scales that provide the tonal framework for a piece of music
15. n. mechanical device used to wind another device that is driven by a spring (as a clock)
16. n. a coral reef off the southern coast of Florida
17. adj. serving as an essential component
18. n. a list of answers to a test
19. n. something crucial for explaining
20. n. a list of words or phrases that explain symbols or abbreviations
21. n. a winged often one-seed indehiscent fruit as of the ash or elm or maple