Meaning of KEY in English

I. ˈkē noun

Etymology: Middle English, from Old English cǣg; akin to Old Frisian kēi key

Date: before 12th century


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


a. : a means of gaining or preventing entrance, possession, or control

b. : an instrumental or deciding factor


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



(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


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. : samara

7. : a system of tones and harmonies generated from a hierarchical scale of seven tones based on a tonic

the key of G major


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. : a decoration or charm resembling a key

10. : a small switch for opening or closing an electric circuit

a telegraph key

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

12. : a free-throw area in basketball

• keyed ˈkēd adjective

• key·less ˈkē-ləs adjective

II. verb

Date: 14th century

transitive verb

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

2. : to regulate the musical pitch of

3. : to bring into harmony or conformity : make appropriate : attune

remarks key ed to a situation

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

5. : to provide with identifying or explanatory cross-references

instructions key ed to accompanying drawings — John Gartner

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

was key ed up over her impending operation

7. : keyboard — often used with in

8. : to be essential to : play the most important part in

defense key ed the victory

intransitive verb

1. : to use a key

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

3. : keyboard

III. adjective

Date: 1913

: important , fundamental

key issues

IV. noun

Etymology: Spanish cayo, from Taino

Date: 1697

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

V. noun

Etymology: by shortening & alteration from kilo

Date: 1968

slang : a kilogram especially of marijuana or heroin

Merriam-Webster's Collegiate English vocabulary.      Энциклопедический словарь английского языка Merriam Webster.