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key - definition and synonyms

 
 
 
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noun [countable] key pronunciation in American English /ki/
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singularkey
pluralkeys
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  1. 1
    a small piece of metal used for opening or locking a door or a container, or for starting the motor of a vehicle
    I could hear someone turning the key in the lock.
    a bunch of keys
    house/car keys
    key to: Where’s the key to the back door?
  2. 2
    [usually singular] the thing that will do most to help you to achieve something
    key to: Proper planning is the key to success.
    The key to our strength lies in our members.
  3. 4
    music a set of musical notes that are based on one particular note
    a major/minor key
    a piece written in the key of C

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