key key /ˈkiː/

adjective

1. () Serving as an essential component  ( primal , cardinal , key , central , fundamental )
   serving as an essential component
    A cardinal rule
   a cardinal rule
    The central cause of the problem
   the central cause of the problem
    An example that was fundamental to the argument
   an example that was fundamental to the argument
    Computers are fundamental to modern industrial structure
   computers are fundamental to modern industrial structure
   

noun

1. () Metal device shaped in such a way that when it is inserted into the appropriate lock the lock's mechanism can be rotated  ( key )
   metal device shaped in such a way that when it is inserted into the appropriate lock the lock's mechanism can be rotated
    I need a key to tighten this bolt
   I need a key to tighten this bolt
   
   
2. () Something crucial for explaining  ( key )
   something crucial for explaining
    The key to development is economic integration
   the key to development is economic integration
   
3. () Pitch of the voice  ( key )
   pitch of the voice
    He spoke in a low key
   he spoke in a low key
   
4. () Any of 24 major or minor diatonic scales that provide the tonal framework for a piece of music  ( tonality , key )
   any of 24 major or minor diatonic scales that provide the tonal framework for a piece of music
   
5. A lever (as in a keyboard) that actuates a mechanism when depressed  ( key )
   a lever (as in a keyboard) that actuates a mechanism when depressed
    I need to replace the "Enter" key on my keyboard
   I need to replace the "Enter" key on my keyboard
   
   
6. The central building block at the top of an arch or vault  ( headstone , key , keystone )
   the central building block at the top of an arch or vault
   
   
7. Mechanical device used to wind another device that is driven by a spring (as a clock)  ( key , winder )
   mechanical device used to wind another device that is driven by a spring (as a clock)
   
8. A generic term for any device whose possession entitles the holder to a means of access  ( key )
   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
   a safe-deposit box usually requires two keys to open it
   
9. A list of words or phrases that explain symbols or abbreviations  ( key )
   a list of words or phrases that explain symbols or abbreviations
   
10. A list of answers to a test  ( key )
    a list of answers to a test
     Some students had stolen the key to the final exam
    some students had stolen the key to the final exam
    
11. (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  ( key , paint )
    (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
    he hit a jump shot from the top of the key
     He dominates play in the paint
    he dominates play in the paint
    
12. A coral reef off the southern coast of Florida  ( cay , Florida key , key )
    a coral reef off the southern coast of Florida
    
13. A winged often one-seed indehiscent fruit as of the ash, elm or maple  ( key , key fruit , samara )
    a winged often one-seed indehiscent fruit as of the ash, elm or maple
    
    
14. A kilogram of a narcotic drug  ( key )
    a kilogram of a narcotic drug
     They were carrying two keys of heroin
    they were carrying two keys of heroin
    

verb

1. () Identify as in botany or biology, for example  ( discover , distinguish , key out , describe , identify , key , name )
   identify as in botany or biology, for example
   
2. Harmonize with or adjust to  ( key )
   harmonize with or adjust to
    Key one's actions to the voters' prevailing attitude
   key one's actions to the voters' prevailing attitude
   
3. (music) regulate the musical pitch of  ( key )
   (music) regulate the musical pitch of
   
4. Vandalize a car by scratching the sides with a key  ( key )
   vandalize a car by scratching the sides with a key
    His new Mercedes was keyed last night in the parking lot
   His new Mercedes was keyed last night in the parking lot
   
5. Provide with a key  ( key )
   provide with a key
    We were keyed after the locks were changed in the building
   We were keyed after the locks were changed in the building
   

 Key

noun

1. United States lawyer and poet who wrote a poem after witnessing the British attack on Baltimore during the War of 1812; the poem was later set to music and entitled 'The Star-Spangled Banner' (1779-1843)  ( Francis Scott Key , Key )
   United States lawyer and poet who wrote a poem after witnessing the British attack on Baltimore during the War of 1812; the poem was later set to music and entitled 'The Star-Spangled Banner' (1779-1843)