A key is a component of a

musical instrument A musical instrument is a device created or adapted to make Music, musical sounds. In principle, any object that produces sound can be considered a musical instrument—it is through purpose that the object becomes a musical instrument. A person ...

, the purpose and function of which depends on the instrument. However, the term is most often used in the context of

keyboard instruments A keyboard instrument is a musical instrument played using a keyboard, a row of levers that are pressed by the fingers. The most common of these are the piano, organ, and various electronic keyboards, including synthesizers and digital pianos ...

, in which case it refers to the exterior part of the instrument that the player physically interacts in the process of sound production. On instruments equipped with tuning machines such as

guitar The guitar is a stringed musical instrument that is usually fretted (with Fretless guitar, some exceptions) and typically has six or Twelve-string guitar, twelve strings. It is usually held flat against the player's body and played by strumming ...

s or

mandolin A mandolin (, ; literally "small mandola") is a Chordophone, stringed musical instrument in the lute family and is generally Plucked string instrument, plucked with a plectrum, pick. It most commonly has four Course (music), courses of doubled St ...

s, a key is part of a tuning machine. It is a worm gear with a key shaped end used to turn a cog, which, in turn, is attached to a post which winds the string. The key is used to make pitch adjustments to a string. With other instruments,

zither Zither (; , from the Greek ''cithara'') is a class of stringed instruments. The modern instrument has many strings stretched across a thin, flat body. Zithers are typically played by strumming or plucking the strings with the fingers or a ...

s and

drum The drum is a member of the percussion group of musical instruments. In the Hornbostel–Sachs classification system, it is a membranophone. Drums consist of at least one membrane, called a drumhead or drum skin, that is stretched over a ...

s, for example, a key is essentially a small wrench used to turn a tuning machine or lug. On

woodwind Woodwind instruments are a family of musical instruments within the greater category of wind instruments. Common examples include flute, clarinet, oboe, bassoon, and saxophone. There are two main types of woodwind instruments: flutes and Ree ...

instruments such as a

flute The flute is a member of a family of musical instruments in the woodwind group. Like all woodwinds, flutes are aerophones, producing sound with a vibrating column of air. Flutes produce sound when the player's air flows across an opening. In th ...

saxophone The saxophone (often referred to colloquially as the sax) is a type of single-reed woodwind instrument with a conical body, usually made of brass. As with all single-reed instruments, sound is produced when a reed on a mouthpiece vibrates to p ...

, keys are finger operated levers used to open or close

tone hole A tone hole is an opening in the body of a wind instrument which, when alternately closed and opened, changes the pitch (music), pitch of the sound produced. Tone holes may serve specific purposes, such as a trill hole or register hole. A tone ...

s, the operation of which effectively shortens or lengthens the resonating tube of the instrument. By doing so, the player is able to physically manipulate the range of resonating sound frequencies capable of being produced by the tubes that has been altered into various “effective” lengths, based on specific key configurations. The keys on the keyboard of a

pipe organ The pipe organ is a musical instrument that produces sound by driving pressurised air (called ''wind'') through the organ pipes selected from a Musical keyboard, keyboard. Because each pipe produces a single tone and pitch, the pipes are provide ...

also open and close various mechanical valves. However, rather than directed influencing the paths the airflow takes within the same tube, the configuration of these valves instead determines through which of the numerous separate organ pipes, each of which tuned for a specific note, the air stream flows through. The keys of an

accordion Accordions (from 19th-century German language, German ', from '—"musical chord, concord of sounds") are a family of box-shaped musical instruments of the bellows-driven free reed aerophone type (producing sound as air flows past a Reed (mou ...

direct the air flow from manually operated

bellows A bellows or pair of bellows is a device constructed to furnish a strong blast of air. The simplest type consists of a flexible bag comprising a pair of rigid boards with handles joined by flexible leather sides enclosing an approximately airtig ...

across various tuned vibrating reeds. On other

keyboard instrument A keyboard instrument is a musical instrument played using a keyboard, a row of levers that are pressed by the fingers. The most common of these are the piano, organ, and various electronic keyboards, including synthesizers and digital piano ...

s, a key may be a lever which mechanically triggers a hammer to strike a group of strings, as on a

piano A piano is a keyboard instrument that produces sound when its keys are depressed, activating an Action (music), action mechanism where hammers strike String (music), strings. Modern pianos have a row of 88 black and white keys, tuned to a c ...

, or an electric switch which energizes an audio oscillator as on an

electronic organ An electric organ, also known as electronic organ, is an electronic keyboard instrument which was derived from the pump organ, harmonium, pipe organ and theatre organ. Originally designed to imitate their sound, or orchestral sounds, it has si ...

or a

synthesizer A synthesizer (also synthesiser or synth) is an electronic musical instrument that generates audio signals. Synthesizers typically create sounds by generating waveforms through methods including subtractive synthesis, additive synthesis a ...

. Piano keys have often been made from

ivory Ivory is a hard, white material from the tusks (traditionally from elephants) and Tooth, teeth of animals, that consists mainly of dentine, one of the physical structures of teeth and tusks. The chemical structure of the teeth and tusks of mamm ...

over the instrument's history, such that a common phrase for playing the piano has been to "tickle the ivories".

References

See also