key

1 of 5

noun (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
a key for winding a clock
2
a
: a means of gaining or preventing entrance, possession, or control
b
: an instrumental or deciding factor
the key to her success
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
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
4
a
: 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
6
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
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
11
a(1)
(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
keyed adjective
keyless adjective

key

2 of 5

adjective

: extremely or crucially important
key issues
a key moment in the game
a key member of the staff

key

3 of 5

verb

keyed; keying; keys

transitive verb

1
: to lock or secure with or as if with a key : fasten: such as
a
: to secure (something, 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
key the strings
3
: to bring into harmony or conformity : make appropriate : attune
remarks keyed to a situation
4
: to identify (a biological specimen) by a key (see key entry 1 sense 3d)
5
: to provide with identifying or explanatory cross-references
instructions keyed to accompanying drawingsJohn Gartner
6
: to make nervous, tense, or excited
usually used with up
was too keyed up to sleep
7
: to enter or input (text or data) by using a keyboard
keying changes to a manuscript
often used with in or into
key in a passwordinformation being keyed into a database
8
: to be essential to : play the most important part in
defense keyed the victory
9
: to vandalize by scratching with a key
someone keyed my car door

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
The middle linebacker was keying on the halfback.
3
: to operate a machine by means of a keyboard : keyboard

key

4 of 5

noun (2)

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

key

5 of 5

noun (3)

slang
: a kilogram especially of marijuana or heroin

Example Sentences

Adjective He's a key player in the organization. The key question is “Can we afford it?”. Underline key words and phrases as you read. Their votes were key in getting the bill passed. Verb The changes to the manuscript are being keyed by the typist. her response was perfectly keyed to the situation See More

Word History

Etymology

Noun (1), Adjective, and Verb

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

Noun (2)

Spanish cayo, from Taino

Noun (3)

by shortening & alteration from kilo

First Known Use

Noun (1)

before the 12th century, in the meaning defined at sense 1a

Adjective

1832, in the meaning defined above

Verb

14th century, in the meaning defined at transitive sense 1

Noun (2)

1693, in the meaning defined above

Noun (3)

1966, in the meaning defined above

Time Traveler
The first known use of key was before the 12th century

Dictionary Entries Near key

Cite this Entry

“Key.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/key. Accessed 2 Feb. 2023.

Kids Definition

key

1 of 4 noun
plural keys
1
a
: a small device that is used to open a lock or start an automobile
b
: a device having the form or function of a key
a key for winding a clock
2
: a means of gaining or preventing entrance, possession, or control
3
a
: something that provides an explanation, solution, or means of identifying
the key to a riddle
b
: a series of phrases or statements that describe characteristics by which plants or animals of a particular group differ and are used to aid in identification
c
: a map legend
4
: one of the levers with a flat surface that is pressed by a finger in operating a machine or playing an instrument
5
: a system of seven musical tones arranged in relation to a keynote from which the system is named
the key of C
6
: a characteristic style or tone
7
: a small switch for opening or closing an electric circuit

key

2 of 4 verb
keyed; keying
1
: to adjust the musical pitch of
2
: to bring into harmony
3
: to make nervous, tense, or excited
usually used with up
all keyed up about the test
4
: to record by operating the keys of a machine
key each price into the cash register

key

3 of 4 adjective
: of great importance
the key people in the organization
the key question is "Can we afford it?"
use key words in an outline

key

4 of 4 noun
: a low island or reef
the Florida Keys

Legal Definition

key

adjective
: of vital importance (as in a business organization) especially so as to be specially insured to the benefit of an employer
key man
key employee insurance

Biographical Definition

Key 1 of 2

biographical name (1)

Francis Scott 1779–1843 American lawyer and author of "The Star-Spangled Banner"

Key

2 of 2

biographical name (2)

John (Phillip) 1961–     prime minister of New Zealand (2008–16)

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