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noun \ˈkē\

Definition of key

  1. 1 a :  a usually metal instrument by which the bolt of a lock is turned b :  any of various devices having the form or function of such a key

  2. 2 a :  a means of gaining or preventing entrance, possession, or control b :  an instrumental or deciding factor

  3. 3 a :  something that gives an explanation or identification or provides a solution <the key to a riddle> b :  a list of words or phrases giving an explanation of symbols or abbreviations c :  an aid to interpretation or identification :  clue d :  an arrangement of the salient characters of a group of plants or animals or of taxa designed to facilitate identification e :  a map legend

  4. 4 a (1) :  cotter pin (2) :  cotter b :  a keystone in an arch c :  a small piece of wood or metal used as a wedge or for preventing motion between parts

  5. 5 a :  one of the levers of a keyboard musical instrument that actuates the mechanism and produces the tones b :  a lever that controls a vent in the side of a woodwind instrument or a valve in a brass instrument c :  a part to be depressed by a finger that serves as one unit of a keyboard

  6. 6 :  samara

  7. 7 :  a system of tones and harmonies generated from a hierarchical scale of seven tones based on a tonic <the key of G major>

  8. 8 a :  characteristic style or tone b :  the tone or pitch of a voice c :  the predominant tone of a photograph with respect to its lightness or darkness

  9. 9 :  a decoration or charm resembling a key

  10. 10 :  a small switch for opening or closing an electric circuit <a telegraph key>

  11. 11 :  the set of instructions governing the encipherment and decipherment of messages

  12. 12 :  a free-throw area in basketball

keyed play \ˈkēd\ adjective
key·less play \ˈkē-ləs\ adjective

Origin of key

Middle English, from Old English cǣg; akin to OldFrisian kēi key

First Known Use: before 12th century

Rhymes with key

b, be, bee, c, cay, cee, Cree, d, dee, Dee, dree, e, fee, flea, flee, free, g, gee, ghee, glee, gree, he, Key, knee, lea, lee, me, mi, p, pea, pee, plea, pree, quay, re, Rhee, scree, sea, see, she, si, ski, spree, sri, t, tea, tee, the, thee, three, ti, tree, twee, Twi, v, vee, we, wee, whee, ye, z, zee




Simple Definition of key

  • : to enter (information) by using the keys of a computer, typewriter, etc.

  • : to have the most important part in (something)

Full Definition of key

  1. transitive verb
  2. 1 :  to lock with or as if with a key :  fasten: as a :  to secure (as a pulley on a shaft) by a key b :  to finish off (an arch) by inserting a keystone

  3. 2 :  to regulate the musical pitch of

  4. 3 :  to bring into harmony or conformity :  make appropriate :  attune <remarks keyed to a situation>

  5. 4 :  to identify (a biological specimen) by a key

  6. 5 :  to provide with identifying or explanatory cross-references <instructions keyed to accompanying drawings — John Gartner>

  7. 6 :  to make nervous, tense, or excited —usually used with up

  8. 7 :  keyboard —often used with in

  9. 8 :  to be essential to :  play the most important part in <defense keyed the victory>

  10. intransitive verb
  11. 1 :  to use a key

  12. 2 :  to observe the position or movement of an opposing player in football in order to anticipate the play —usually used with on

  13. 3 :  keyboard

Examples of key

  1. The changes to the manuscript are being keyed by the typist.

  2. <her response was perfectly keyed to the situation>

14th Century

First Known Use of key

14th century




Simple Definition of key

  • : extremely important

Full Definition of key

  1. :  important, fundamental <key issues>

Examples of key

  1. He's a key player in the organization.

  2. The key question is Can we afford it?.

  3. Underline key words and phrases as you read.

  4. Their votes were key in getting the bill passed.


First Known Use of key





Definition of key

  1. :  a low island or reef; specifically :  any of the coral islets off the southern coast of Florida

Origin of key

Spanish cayo, from Taino

First Known Use: 1697




Definition of key


  1. :  a kilogram especially of marijuana or heroin

Origin of key

by shortening & alteration from kilo

First Known Use: 1968

Other Drug/Tobacco Terms


biographical name \ˈkē\

Definition of Key

  1. Francis Scott 1779–1843 Am. lawyer & author of “The Star-Spangled Banner”


biographical name

Definition of Key

  1. John (Phillip) 1961–     prime min. of New Zealand (2008–  )

Seen and Heard

What made you want to look up key? Please tell us where you read or heard it (including the quote, if possible).


February 5, 2016

bread traditionally eaten on Shabbat

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