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English definition of “key”

key

noun [C]
 
 
/kiː/
FOR LOCKS A1 a piece of metal cut into a particular shape and used for locking things such as doors, or for starting an engine: I've lost my car keys.Locking and bolting
METHOD B1 a way of explaining or achieving something: Hard work is the key to success.Ways of achieving things
KEYBOARD B2 one of the parts you press with your fingers on a keyboard or musical instrument to produce letters, numbers, or to make a soundComputer hardwareKeyboard instruments
MUSIC a set of musical notes based on one particular note: the key of D majorTechnical music terms
SYMBOLS a list that explains the symbols on a map or pictureMaps and map-makingSigns, signals and symbolsSpecific signs and symbols
ANSWERS A2 a list of answers to an exercise or game → See also under lock and keySolving and solutions
(Definition of key noun from the Cambridge Learners Dictionary © Cambridge University Press)
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