key

key, in music

key.

1 In music, term used to indicate the scale from which the tonal material of a given composition is derived. To say, for example, that a composition is in the key of C major means that it uses as its basic tonal material the tones of that scale which is associated with C major, and that its harmony employs the chords built on the tones of that scale. C is then the keynote, and the C major triad, or the notes CEG, the tonic chord of the composition. In addition to the seven tones of the C major scale, however, the remaining five tones of the chromatic scale may appear as auxiliary tones, and chords may be borrowed from other keys. Modulation to another key may take place, but if there is a return to the original key the whole composition is said to be in the key of C. At the beginning of a composition, its key is usually indicated by a key signature (see musical notation). A term usually used synonymously with key is tonality. Absence of a feeling of key is called atonality. The concept of keynotes was developed gradually during the 16th and 17th cent. and its partial or total abandonment was a feature of the modernism of the early and mid-20th cent. Polytonality, the employment of two or more keys simultaneously, has been used by some 20th-century composers.

2 Also in music, in reference to musical instruments the term key refers to a lever depressed by the player's finger or, in the case of the pedal keyboard of the organ, the foot. In woodwind instruments the keys control covers on the holes that shorten the vibrating column of air. In brass winds they control the valves that lower the pitch of the instrument by lengthening the tube.

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key, in mechanics

key, in mechanics: see lock and key.

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key

In music, system of pitches and harmonies generated from a scale of seven tones, one of which is predominantly important. Keys are a basic element of tonality and represent an outgrowth of modal music (see church mode). When a given piece is said to be “in C,” C is its “tonic,” or central tone. Most Western music from about 1700 until about 1900 is characterized by use of the 12 major and 12 minor keys of the tonal system.

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(1) A keyboard button. See qwerty keyboard.

(2) A numeric code that is used to encrypt text for security purposes. See key length, key space, cryptography and salt.

(3) A data field in a record. See key field and sort key.

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key

attribute of the personified Fidelity. [Art: Hall, 184]

See : Faithfulness

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1.	(database)	key - A value used to identify a record in a database, derived by applying some fixed function to the record. The key is often simply one of the fields (a column if the database is considered as a table with records being rows, see "key field"). Alternatively the key may be obtained by applying some function, e.g. a hash function, to one or more of the fields. The set of keys for all records forms an index. Multiple indexes may be built for one database depending on how it is to be searched.
2.	(cryptography)	key - A value which must be fed into the algorithm used to decode an encrypted message in order to reproduce the original plain text. Some encryption schemes use the same (secret) key to encrypt and decrypt a message, but public key encryption uses a "private" (secret) key and a "public" key which is known by all parties.
3.	(hardware)	key - An electromechanical keyboard button.