A key is a piece of metal that fits inside a lock and turns to open it. You might have a key ring with a house key, a car key, and maybe several more keys.

A key is typically cut from metal, although many hotels use plastic keys for their guest rooms. If you are told that your attendance is key, you know you have to go. Another meaning of key is a button or lever you press with your fingers, like a piano key or a typewriter key. A key is also an explanation, like the answer key for a test or the key to success. And when you sing in key, you have the correct pitch.

Definitions of key
  1. noun
    metal device shaped in such a way that when it is inserted into the appropriate lock the lock's mechanism can be rotated
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    ignition key
    a key that operates the ignition switch of an automotive engine
    key for raising or drawing back a latch or opening an outside door
    master, master key, passe-partout, passkey
    key that secures entrance everywhere
    skeleton key
    a passkey with much of the bit filed away so that it can open different locks
    type of:
    an instrumentality invented for a particular purpose
  2. noun
    mechanical device used to wind another device that is driven by a spring (as a clock)
    synonyms: winder
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    watch key
    winder consisting of a key with a square hole; used for winding some watches
    type of:
    mechanical device
    mechanism consisting of a device that works on mechanical principles
  3. noun
    a lever (as in a keyboard) that actuates a mechanism when depressed
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    backspace, backspace key, backspacer
    the typewriter key used for back spacing
    command key, control key
    (computer science) the key on a computer keyboard that is used (in combination with some other key) to type control characters
    return, return key
    the key on electric typewriters or computer keyboards that causes a carriage return and a line feed
    shift, shift key
    the key on the typewriter keyboard that shifts from lower-case letters to upper-case letters
    space bar
    the bar-shaped typewriter key that introduces spaces when used
    tab, tab key
    the key on a typewriter or a word processor that causes a tabulation
    telegraph key
    key consisting of a lever that sends a telegraph signal when it is depressed and the circuit is closed
    type of:
    a rigid bar pivoted about a fulcrum
  4. noun
    a generic term for any device whose possession entitles the holder to a means of access
    “a safe-deposit box usually requires two keys to open it”
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    type of:
    positive identification
    evidence proving that you are who you say you are; evidence establishing that you are among the group of people already known to the system; recognition by the system leads to acceptance
  5. verb
    provide with a key
    “We were keyed after the locks were changed in the building”
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    type of:
    furnish, provide, render, supply
    give something useful or necessary to
  6. verb
    vandalize a car by scratching the sides with a key
    “His new Mercedes was keyed last night in the parking lot”
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    type of:
    vandalise, vandalize
    destroy wantonly, as through acts of vandalism
  7. noun
    something crucial for explaining
    “the key to development is economic integration”
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    type of:
    thought that makes something comprehensible
  8. noun
    a list of answers to a test
    “some students had stolen the key to the final exam”
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    type of:
    list, listing
    a database containing an ordered array of items (names or topics)
  9. noun
    a list of words or phrases that explain symbols or abbreviations
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    key word
    a word that is used as a pattern to decode an encrypted message
    type of:
    list, listing
    a database containing an ordered array of items (names or topics)
  10. verb
    identify as in botany or biology, for example
  11. verb
    harmonize with or adjust to
    key one's actions to the voters' prevailing attitude”
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    type of:
    harmonise, harmonize, reconcile
    bring into consonance or accord
  12. adjective
    serving as an essential component
    synonyms: cardinal, central, fundamental, primal
    important, of import
    of great significance or value
  13. noun
    any of 24 major or minor diatonic scales that provide the tonal framework for a piece of music
    synonyms: tonality
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    atonalism, atonality
    the absence of a key; alternative to the diatonic system
    major key, major mode
    a key whose harmony is based on the major scale
    minor key, minor mode
    a key based on the minor scale
    home key, tonic key
    the basic key in which a piece of music is written
    type of:
    musical notation
    (music) notation used by musicians
  14. noun
    pitch of the voice
    “he spoke in a low key
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    type of:
    the property of sound that varies with variation in the frequency of vibration
  15. verb
    regulate the musical pitch of
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    type of:
    chord, harmonise, harmonize
    bring into consonance, harmony, or accord while making music or singing
  16. noun
    a kilogram of a narcotic drug
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    type of:
    kg, kilo, kilogram
    one thousand grams; the basic unit of mass adopted under the Systeme International d'Unites
  17. noun
    a winged often one-seed indehiscent fruit as of the ash or elm or maple
    synonyms: key fruit, samara
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    type of:
    small dry indehiscent fruit with the seed distinct from the fruit wall
  18. noun
    a coral reef off the southern coast of Florida
    synonyms: Florida key, cay
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    type of:
    coral reef
    a reef consisting of coral consolidated into limestone
  19. noun
    the central building block at the top of an arch or vault
    synonyms: headstone, keystone
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    coign, coigne, quoin
    the keystone of an arch
    type of:
    building block
    a block of material used in construction work
  20. noun
    (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
    “he hit a jump shot from the top of the key
    synonyms: paint
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    type of:
    an area reserved for some particular purpose
Word Family

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