key

1a : 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 key for winding a clock

2a : a means of gaining or preventing entrance, possession, or control

b : an instrumental or deciding factor the key to her success

3a : 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 a pronunciation key in a dictionary

c : an aid to interpretation or identification : clue a key to understanding their motivation

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

4a : a part to be depressed by a finger that serves as one unit of a keyboard also : a representation of such a key (such as a space delineated on a touch screen) Tiny keys on your iPhone's screen can be difficult to hit accurately. — Cherlynn Low

b : one of the levers of a keyboard musical instrument that actuates the mechanism and produces the tones

c : a lever that controls a vent in the side of a woodwind instrument or a valve in a brass instrument

5 : a system of tones and harmonies generated from a hierarchical scale of seven tones based on a tonic the key of G major

6a : 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

7 : a decoration or charm resembling a key

8 : a small switch for opening or closing an electric circuit a telegraph key

9 : the set of instructions governing the encipherment and decipherment of messages an encryption key

10 : a free-throw area in basketball : free throw lane a jump shot from the top of the key

11a(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

12 : samara

Definition of key

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