Key

/kiː/ adj, name, noun, verb, slang

adj, name, noun, verb, slang ·Top 500 ·Elementary level

Meaning at a glance

  • Primary sense: An object designed to open and close a lock.
  • Grammar: key is listed as adj, name, noun, verb, slang.
  • Nearest alternatives: access, accommodate, accord, accounting materiality.
  • Useful contrasts: clear key, delete, erase.
  • Usage evidence: The key question is not what can I gain but what do I have to lose.

How to use "key"

  1. Start with the primary definition, then check the part of speech before placing the word in a sentence.
  2. Compare nearby synonyms to make sure "key" carries the exact meaning, tone, and strength you need.
  3. Use the example sentence as a context check. If your sentence uses the word differently, confirm that the grammar still fits.

Meaning check

  • Does the word fit the sentence's grammar?
  • Does it match the intended tone rather than only the dictionary definition?
  • Would a simpler synonym be clearer for the reader?
  • Is there enough surrounding context to prevent ambiguity?

Source and review context

This entry combines structured lexical data with WordToolSet review checks. Definitions, examples, synonyms, and usage notes may come from different source tables, so the page is designed to show evidence from more than one angle before you rely on "key" in a final draft.

If a word has several senses, prefer the sense that matches your sentence's grammar and surrounding context. A correct definition can still be the wrong choice when the sentence needs a different register, emphasis, or level of specificity.

Before you rely on this definition

Read the first definition as a starting point, then check the example, synonyms, and part of speech before treating "key" as the right word for your sentence.

If your draft is formal, technical, persuasive, or sensitive, compare "key" with a nearby alternative so the final choice matches both meaning and reader expectation.

Compare nearby meanings

  • Use synonyms when you need a softer, stronger, simpler, or more specific word.
  • Use antonyms to check the boundary of the meaning and avoid accidental contrast.
  • Use the example sentence to confirm the word behaves naturally in context.
  • Keep the original wording when a replacement adds complexity without improving precision.

Definition decision workflow

1. Identify the role

Check whether "key" is acting as adj, name, noun, verb, slang in your sentence. A definition is only useful when the grammar matches the way the word is being used.

2. Test the nearest option

Compare it with "access" and other nearby choices to see whether the sentence needs a softer, stronger, or more familiar word.

3. Confirm with context

Use the example sentence below as an evidence check, then read your own sentence out loud to catch tone or rhythm problems.

Review note: Definition pages are checked for source coverage, sentence evidence, synonym support, and editorial insight before they are treated as approval-ready pages. If the evidence is too thin, the page remains available to users but is kept out of the approval-facing indexed inventory.

Final meaning check

Before publishing a sentence with "key", ask whether the word helps the reader understand the idea faster. A precise word should reduce confusion, not simply make the sentence look more polished.

When the definition, synonym evidence, and example context point in the same direction, the word is usually a safer choice. When they conflict, revise the sentence or choose a clearer alternative.

Definitions

Noun
  1. 1
    An object designed to open and close a lock. countable

    "We tiptoed into the house, up the stairs and along the hall into the room where the Professor had been spending so much of his time. 'Twas locked, of course, but the Deacon man got a big bunch of keys out of his pocket and commenced to putter with the lock."

  2. 2
    One of a string of small islands.

    "the Florida Keys"

  3. 3
    A kilogram, especially of a recreational drug. slang

    "So starting with ten keys of cocaine and two keys of heroin, Derrick put his plan in motion. Soon every major drug dealer and gang chief from Chicago Avenue to Evanston was in his pocket."

  4. 4
    Alternative form of quay. alt-of, alternative
  5. 5
    metal device shaped in such a way that when it is inserted into the appropriate lock the lock's mechanism can be rotated wordnet
Show 46 more definitions
  1. 6
    An object designed to fit between two other objects (such as a shaft and a wheel) in a mechanism and maintain their relative orientation.
  2. 7
    a lever (as in a keyboard) that actuates a mechanism when depressed wordnet
  3. 8
    A crucial step or requirement.

    "The key to solving this problem is persistence."

  4. 9
    the central building block at the top of an arch or vault wordnet
  5. 10
    A small guide explaining symbols or terminology, especially the legend on a map or chart.

    "The key says that A stands for the accounting department."

  6. 11
    mechanical device used to wind another device that is driven by a spring (as a clock) wordnet
  7. 12
    A guide to the correct answers of a worksheet or test.

    "Some students cheated by using the answer key."

  8. 13
    pitch of the voice wordnet
  9. 14
    One of several small, usually square buttons on a typewriter or computer keyboard, mostly corresponding to text characters.

    "Press the Escape key."

  10. 15
    something crucial for explaining wordnet
  11. 16
    In musical instruments, one of the valve levers used to select notes, such as a lever opening a hole on a woodwind.
  12. 17
    a generic term for any device whose possession entitles the holder to a means of access wordnet
  13. 18
    In instruments with a keyboard such as an organ or piano, one of the levers, or especially the exposed front end of it, which are depressed to cause a particular sound or note to be produced.
  14. 19
    a list of words or phrases that explain symbols or abbreviations wordnet
  15. 20
    A scale or group of pitches constituting the basis of a musical composition.

    "the key of B-flat major"

  16. 21
    a list of answers to a test wordnet
  17. 22
    A scale or group of pitches constituting the basis of a musical composition.; The lowest note of a scale; keynote.
  18. 23
    any of 24 major or minor diatonic scales that provide the tonal framework for a piece of music wordnet
  19. 24
    A scale or group of pitches constituting the basis of a musical composition.; In musical theory, the total melodic and harmonic relations, which exist between the tones of an ideal scale, major or minor; tonality.
  20. 25
    (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 wordnet
  21. 26
    A scale or group of pitches constituting the basis of a musical composition.; In musical theory and notation, the tonality centering in a given tone, or the several tones taken collectively, of a given scale, major or minor.
  22. 27
    a coral reef off the southern coast of Florida wordnet
  23. 28
    A scale or group of pitches constituting the basis of a musical composition.; In musical notation, a sign at the head of a staff indicating the musical key.
  24. 29
    a winged often one-seed indehiscent fruit as of the ash or elm or maple wordnet
  25. 30
    The general pitch or tone of a sentence or utterance. figuratively

    "2. Queen.[…]Deere Glasse of Ladies Bid him that we whom flaming war doth scortch, Vnder the shaddow of his Sword, may coole us: Require him he advance it ore our heades; Speak't in a womans key: like such a woman As any of us three; weepe ere you faile; lend us a knee; But touch the ground for us no longer time Then a Doves motion, when the head's pluckt off: Tell him if he i'th blood cizd field, lay swolne Showing the Sun his Teeth; grinning at the Moone What you would doe."

  26. 31
    a kilogram of a narcotic drug wordnet
  27. 32
    A modification of an advertisement so as to target a particular group or demographic.

    "Another popular way to key ads and mailings is to use a suite number, room number, department number, desk number, etc. as part of the ordering address. With a classified ad, using such a key may increase your ad cost."

  28. 33
    An indehiscent, one-seeded fruit furnished with a wing, such as the fruit of the ash and maple; a samara.
  29. 34
    A manual electrical switching device primarily used for the transmission of Morse code. historical
  30. 35
    A piece of information (e.g., a password or passphrase) used to encode or decode a message or messages.
  31. 36
    A password restricting access to an IRC channel. Internet

    "if you know someone who is in the channel, you can query them and ask for the key."

  32. 37
    In a relational database, a field used as an index into another table (not necessarily unique).
  33. 38
    A value that uniquely identifies an entry in a container.
  34. 39
    Any of various tools comparable to a wrench (spanner) or driver, or, in some cases, also called a wrench or driver.

    "radiator key"

  35. 40
    A series of logically organized groups of discriminating information which aims to allow the user to correctly identify a taxon.
  36. 41
    A piece of wood used as a wedge.
  37. 42
    The last board of a floor when laid down.
  38. 43
    A keystone.
  39. 44
    That part of the plastering which is forced through between the laths and holds the rest in place.
  40. 45
    A wooden wedge, driven sideways between a bullhead rail and a cast-iron chair, to keep the rail securely in position.
  41. 46
    The degree of roughness, or retention ability of a surface to have applied a liquid such as paint, or glue.

    "The door panel should be sanded down carefully to provide a good key for the new paint."

  42. 47
    The thirty-third card of the Lenormand deck.
  43. 48
    The black ink layer, especially in relation to the three color layers of cyan, magenta, and yellow. See also CMYK.
  44. 49
    A color to be masked or made transparent.

    "You can easily create this type of user interface by creating a bitmap with certain portions set to a predefined color you want to use as the transparency key."

  45. 50
    The free-throw lane together with the circle surrounding the free-throw line, the free-throw lane having formerly been narrower, giving the area the shape of a skeleton key hole.

    "He shoots from the top of the key."

  46. 51
    A key position player (a tall forward or defender).

    ""It just means that one of them here and there will need to play on a small-to-medium forward (instead of Riewoldt) which is fine. Our keys are pretty agile.""

Verb
  1. 1
    To fit (a lock) with a key.
  2. 2
    harmonize with or adjust to wordnet
  3. 3
    To fit (pieces of a mechanical assembly) with a key to maintain the orientation between them.
  4. 4
    regulate the musical pitch of wordnet
  5. 5
    To mark or indicate with a symbol indicating membership in a class.

    "So I worked on a tissue-paper copy of the perimeter plan, outlining groupings of plants of the same species and keying them with letters for the species."

Show 15 more definitions
  1. 6
    identify as in botany or biology, for example wordnet
  2. 7
    To depress (a telegraph key).
  3. 8
    vandalize a car by scratching the sides with a key wordnet
  4. 9
    To operate (the transmitter switch of a two-way radio).
  5. 10
    provide with a key wordnet
  6. 11
    (more usually to key in) To enter (information) by typing on a keyboard or keypad.

    "Our instructor told us to key in our user IDs."

  7. 12
    To vandalize (a car, etc.) by scratching with an implement such as a key. colloquial

    "He keyed the car that had taken his parking spot."

  8. 13
    To link (as one might do with a key or legend).

    "The American Heart Association has prepared their own guide to classification and, keying it with the Standard Nomenclature of Diseases, have done much to encourage a concise yet complete diagnosis."

  9. 14
    To be identified as a certain taxon when using a key. intransitive
  10. 15
    To modify (an advertisement) so as to target a particular group or demographic. transitive

    "Keying advertisements and counting the number of inquiries received or the number of coupons returned to indicate the "pulling power" of a particular piece of copy or the coverage of a particular advertising medium."

  11. 16
    To attune to; to set at; to pitch.

    "To Ethel alone she addressed a stray remark, keyed below the sound of other voices."

  12. 17
    To fasten or secure firmly; to fasten or tighten with keys or wedges.

    "they Mouldered and keyed the Portico Arches with Pieces of Stone, because Brick was not strong enough"

  13. 18
    To prepare for plastering by adding the key (that part of the plastering which is forced through between the laths and holds the rest in place).
  14. 19
    To provide an arch with a keystone.

    "The last arch in the permanant ^([sic]) bridge was keyed on March 26, 1850, and a single track was brought into use for goods trains on July 20."

  15. 20
    Clipping of chromakey. abbreviation, alt-of, clipping

    "After keying the background, you’d be left with a transparent background, where you can install anything—from images to videos that blend seamlessly into the main subject of the shot."

Adjective
  1. 1
    Indispensable, supremely important. not-comparable, usually

    "He is the key player on his soccer team."

  2. 2
    Important, salient. not-comparable, usually

    "She makes several key points."

Adjective
  1. 1
    serving as an essential component wordnet
Proper Noun
  1. 1
    A surname.

Synonyms

All synonyms
accessaccommodateaccordaccounting materialityachromatismadapt

Antonyms

clear keydeleteeraseincidental

Example

"The key question is not what can I gain but what do I have to lose."

Common questions

What does "key" mean?

An object designed to open and close a lock.

What is a synonym for "key"?

Common synonyms include: access, accommodate, accord, accounting materiality, achromatism, adapt.

How do you use "key" in a sentence?

The key question is not what can I gain but what do I have to lose.

How do you pronounce "key"?

Pronounced /kiː/.

Etymology

Etymology 1

From Middle English keye, kaye, keiȝe, from Old English cǣġ (“key, solution, experiment”) (whence also Scots key and kay (“key”)), from Anglo-Frisian Proto-West Germanic *kaiju, of uncertain origin. The only sure cognates are Saterland Frisian Koai (“key”), West Frisian kaai (“key”), and North Frisian kai, koie (“key”). Possibly from Proto-Germanic *kēgaz, *kēguz (“stake, post, pole”), from Proto-Indo-European *ǵogʰ-, *ǵegʰ-, *ǵegʰn- (“branch, stake, bush”), which would make it cognate with Middle Low German kāk (“whipping post, pillory”), and perhaps to Middle Dutch keige (“javelin, spear”) and Middle Low German keie, keige (“spear”). For the semantic development, note that medieval keys were simply long poles (ending in a hook) with which a crossbar obstructing a door from the inside could be removed from the outside, by lifting it through a hole in the door. Liberman has noted, however, "The original meaning of *kaig-jo- was presumably '*pin with a twisted end.' Words with the root *kai- followed by a consonant meaning 'crooked, bent; twisted' are common only in the North Germanic languages."

Etymology 2

Variant of cay, from Spanish cayo, from Taíno cayo (“small island”)

Etymology 3

Clipping of kilogram or kilo.

More for "key"

Synonyms

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