Word.ws English Dictionary

key

/kiː//ki/

key noun: an object designed to open and close a lock or to activate or deactivate something, especially a length of metal inserted into a narrow opening on the lock to which it is matched (keyed). Also the clipping of chromakey.

key: an object designed to open and close a lock or to activate or deactivate something, especially a...
Image: DIVYALAKSHWIN, CC BY-SA 4.0, via Wikimedia Commons

Noun (1)

key (plural keys)

  1. (countable) An object designed to open and close a lock or to activate or deactivate something, especially a length of metal inserted into a narrow opening on the lock to which it is matched (keyed).
    • This key is to the backdoor.
    • insert the key into the lock (formal); put the key in the lock (informal)
    1. (countable) A card or fob that electronically signals a lock to open.
      • My hotel room key is a card.
      • The gym will give you a fob that opens the door.
    2. (countable, figuratively) A piece of information (e.g., a password or passphrase) used to encode or decode a message or messages.
    3. (Internet, countable) A password restricting access to an IRC channel.
      • if you know someone who is in the channel, you can query them and ask for the key.2000, Robert Erdec, “Re: Help; mIRC32; unable to resolve server arnes.si”, in alt.irc.mirc (Usenet)
    4. (countable, slang) A key bump (A portion of a recreational drug in powdered form that is snorted from a key or similar small object.)
      • I saw him snort a key at the party.
    5. (countable) Any of various tools comparable to a wrench (spanner) or driver, which have a specialized end that matches a fixture, analogously to a lock's key.
      • The exterminator will bring a key thingy that can open the bait boxes.
      • Safe-deposit boxes open with a special key.
  2. (machinery) A cotter pin.
  3. A piece of wood used as a wedge.
  4. The last board of a floor when laid down.
  5. A keystone.
  6. That part of the plastering which is forced through between the laths and that holds the rest in place.
  7. A wooden wedge, driven sideways between a bullhead rail and a cast-iron chair, to keep the rail securely in position.
  8. (figuratively) A crucial step or requirement.
    • Persistence is the key to solving this problem.
    • The key to winning that game is your strategy at the beginning.
    1. (broadly, figuratively) An idea, theory or observation that explains, justifies or renders (something) comprehensible.
      • The key to his proposal is that he thinks this company is dying and needs radical change.
    2. (figuratively) A deciding factor.
      • Her charm is the key to her success.
  9. A small guide explaining symbols, abbreviations or terminology, especially the legend on a map or chart.
    • map key
    • The key says that A stands for the accounting department.
  10. A guide to the correct answers of a worksheet or test.
    • Some students cheated by using the key.
    Synonyms:
    answer key
  11. A series of logically organized groups of discriminating information which aims to allow the user to correctly identify a taxon; a taxonomic key.
  12. A value that uniquely identifies an entry in a container.
Show 14 more meaningsShow fewer meanings
  1. In a relational database, a field used as an index into another table (not necessarily unique).
  2. One of several small, usually square buttons on a typewriter or computer keyboard, mostly corresponding to text characters.
    • Press the Escape key.
    • A key; B key, etc.
  3. In musical instruments, one of the valve levers used to select notes, such as a lever opening a hole on a woodwind.
    • piano key
  4. 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.
  5. A scale or group of pitches constituting the basis of a musical composition.
    • the key of B-flat major
    • A girl, it is true, has always lived in a glass house among reproving relatives, whose word was law; she has been bred up to sacrifice her judgments and take the key submissively from dear papa; and it is wonderful how swiftly she can change her tune into the husband's.1881, R.L. Stevenson, Virginibus Puerisque
    1. The lowest note of a scale; keynote.
    2. In musical theory, the total melodic and harmonic relations, which exist between the tones of an ideal scale, major or minor; tonality.
    3. 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.
    4. In musical notation, a sign at the head of a staff indicating the musical key.
    5. (figuratively) The general pitch or tone of a sentence or utterance.
      • 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...1613–1614 (date written), John Fletcher, William Shak[e]speare, The Two Noble Kinsmen: […], London: […] Tho[mas] Cotes, for Iohn Waterson; […], published 1634, →OCLC, Act I, scene i, page 1
      • ?, William Cowper, Conversation
        You fall at once into a lower key.
    6. (broadly, figuratively) A modification of an advertisement so as to target a particular group or demographic.
  6. An item of decor shaped like a key.
  7. An indehiscent, one-seeded fruit furnished with a wing, such as the fruit of the ash and maple; a samara.
    Synonyms:
    key-fruit
  8. 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.
  9. The thirty-third card of the Lenormand deck, which features an image of a key.
  10. The overall color tone of a painting or other visual art, with a high key indicating generally light colors and a low key indicating generally dark colors.
  11. (print and film) The black ink layer, especially in relation to the three color layers of cyan, magenta, and yellow. See also CMYK.
  12. 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.2004, Mark Schmidt, Simon Robinson, Microsoft Visual C# .NET 2003 Developer's Cookbook, page 195
    • There are key controls that adjust the “slice level” or the level at which the key kicks-in and starts cutting a hole for the “fill” […] Chroma key is another form of keying, which derives the key cutter or hole from a selected color.2016, Jerry C. Whitaker, The SBE Broadcast Engineering Handbook
  13. (historical) A manual electrical switching device primarily used for the transmission of Morse code.
  14. The degree of roughness, or the ability of a surface to retain an applied liquid, such as paint or glue.
    • The door panel should be sanded down carefully to provide a good key for the new paint.

Adjective

key (not generally comparable, comparative keyer or more key, superlative keyest or most key)

  1. (not comparable, usually) Indispensable, supremely important.
    • He is the key player on his soccer team.
    • Paradoxically enough, however, in general only the parties of the Left have done most to spread the belief that it was the numerical strength of the opposing material interests which decided political issues, whereas in practice these same parties have regularly and successfully acted as if they...1949, F. A. Hayek, “The Intellectuals and Socialism”, in University of Chicago Law Review, volume 16, number 3, Chicago: University of Chicago, →DOI, page 418
  2. (not comparable, usually) Important, salient.
    • She makes several key points.
    • Throughout the 1500s, the populace roiled over a constellation of grievances of which the forest emerged as a key focal point. The popular late Middle Ages fictional character Robin Hood, dressed in green to symbolize the forest, dodged fines for forest offenses and stole from the rich to give to...2006, Edwin Black, chapter 2, in Internal Combustion

Verb

key (third-person singular simple present keys, present participle keying, simple past and past participle keyed)

  1. To fit (a lock) with a key.
  2. To fit (pieces of a mechanical assembly) with a key to maintain the orientation between them.
  3. 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.1996 January, Garden Dsign Ideas, second printing, Taunton Press, →ISBN, page 25
    • The volume closes with thirty pages of "Notes, critical and explanatory," in which Thomson provides seventy-six longer or shorter notes keyed to specific sections of the synopsis.2001, Bruce M. Metzger, The Bible in Translation, →ISBN, page 87
  4. To depress (a telegraph key).
  5. To operate (the transmitter switch of a two-way radio).
  6. (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. (colloquial) To vandalize (a car, etc.) by scratching with an implement such as a key.
    • He keyed the car that had taken his parking spot.
  8. 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.1960, Richard L. Masland, “Classification of the Epilepsies”, in Epilepsia, volume 1, page 516
    • The workman's compensation system rests on incentives (premium payments) that are keyed to the immediate and relatively undeniable nature of injuries; […]1976, Nicholas Askounes Ashford, Crisis in the Workplace: Occupational Disease and Injury, page 19
  9. (intransitive) To be identified as a certain taxon when using a key.
  10. (transitive) To modify (an advertisement) so as to target a particular group or demographic.
    • 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.1936, John Freeman Pyle, Marketing Principles, Organization and Policies, page 711
    • 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. Why? Because you're using an extra word or two to key the ad.1998, Mail Order Success Secrets
  11. To attune to; to set at; to pitch.
    • To Ethel alone she addressed a stray remark, keyed below the sound of other voices.1930, Norman Lindsay, Redheap, Sydney, N.S.W.: Ure Smith, →OCLC, page 23
  12. 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 enough1744, Roger North, The Life of the Honourable Sir Dudley North
  13. 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. 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 20.1950 September, “Centenary of the Royal Border Bridge”, in Railway Magazine, page 637

Noun (2)

key (plural keys)

  1. One of a string of small islands.
    • the Florida Keys

Noun (3)

key (plural keys)

  1. (slang) A kilogram, especially of a recreational drug.
    • 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.2010, David J. Silas, Da Block, page 41
    Synonyms:
    kay

Noun (4)

key (plural keys)

  1. (Australian rules football) 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."2023 April 7, “'Bit of a surprise': Dogs bemused by Tigers' selection call”, in Australian Football League, retrieved 27 Jul 2025

Proper noun capitalized: Key

Key

  1. A surname.

Also used as

key is also the clipping of chromakey.

key is also the alternative form of quay.

key meaning in Hindi, Tamil, Marathi and Urdu

key in Hindi

device designed to open and close a lock
ताली tālī, चाबी cābī, कुंजी kuñjī, कुंजिका kuñjikā
button on a typewriter or computer keyboard
बटन baṭan

key in Tamil

device designed to open and close a lock
சாவி cāvi, திறவுகோல் tiṟavukōl, திறப்பு tiṟappu

key in Marathi

device designed to open and close a lock
चावी ċāvī, किल्ली killī
button on a typewriter or computer keyboard
कळ kaḷ

key in Urdu

device designed to open and close a lock
تالی tālī, چابی cābī
More languagesFewer languages
key in Bengali
চাবি cabi
key in Telugu
తాళంచెవి tāḷañcevi, బీగంచెవి bīgañcevi
key in Malayalam
താക്കോല് tākkōl
key in Kannada
ಬೀಗದ ಕೈ bīgada kai, ಕೀಲಿಕೈ kīlikai, ಚಾವಿ cāvi
key in Punjabi
ਕੁੰਜੀ kuñjī
key in Gujarati
ચાવી cāvī, કૂંચી kū̃cī, કલીદ kalīd
key in Odia
ଚାବି cābi
key in Sanskrit
कुञ्चिका kuñcikā
key in Sinhala
යතුර yatura
key in Assamese
চাবি sabi
key in Nepali
साचो sāco
key in Pashto
کونجي kwənji, کلۍ kələy, چابي čābi
key in Tagalog
susi
key in Arabic
مِفْتَاح miftāḥ, مفتاح muftāḥ, مُفْتاح muftāḥ, ساروت sārūt
key in Malay
kunci, kekunci, tatal
key in Indonesian
kunci, tuts, tombol
key in Persian
کَلِید kalīd, کِلِید kilīd, کَلید kalid, کِلید kelid
key in Thai
กุญแจ gun-jɛɛ, ลูกกุญแจ lûuk-gun-jɛɛ, ปุ่ม bpùm
key in Vietnamese
chìa khoá, khoá, chìa, chìa khóa
key in Myanmar
သော့တံ sau.tam, သော့ sau.
Sindhi
ڪُنجيِ kunjī, چاٻيِ cāḇī

Examples of key in a sentence

  • apartment key; room key; spare key
  • '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.1913, Joseph C[rosby] Lincoln, chapter XIII, in Mr. Pratt’s Patients, New York, N.Y.; London: D[aniel] Appleton and Company, →OCLC:
  • Those who are accustomed to reason have got the true key of books.a. 1705, John Locke, “Of the Conduct of the Understanding”, in Posthumous Works of Mr. John Locke: […], London: […] A[wnsham] and J[ohn]...
  • Lukas intimates that one of Disney's key attractions was "Main Street USA,” which "mimicked a downtown business district just as Southdale" had done.2007, Mark H. Moss, Shopping as an Entertainment Experience, page 46:
  • The question of the plausibility of the counter-factual is seen as key in all three discussions of allohistorical fiction (as it is in Demandt's and Ferguson's examinations of allohistory) (cf.2014 October 14, David Malcolm, “The Great War Re-Remembered: Allohistory and Allohistorical Fiction”, in Martin Löschnigg, Marzena...

All 40 example sentences with key

Synonyms of key

All synonyms of key

Forms of key

Noun
pluralkeys
alternative formcay
alternative formki
alternative formkeye
alternative formkee
Adjective
comparativekeyer
comparativemore key
superlativekeyest
superlativemost key
Verb
third-person singular presentkeys
present participlekeying
past participlekeyed
pastkeyed

Past tense of key: keyed

Plural of key: keys

Origin of key

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."

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

Clipping of kilogram or kilo.

Words formed from key

Phrases with key

145 more phrasesFewer phrases

Words that rhyme with key

48 more rhymesFewer rhymes

Questions about key

What does key mean?
Key means an object designed to open and close a lock or to activate or deactivate something, especially a length of metal inserted into a narrow opening on the lock to which it is matched (keyed).
What is key in Hindi?
Key in Hindi is ताली (tālī), चाबी (cābī), कुंजी (kuñjī). See Key meaning in Hindi.
How do you use key in a sentence?
apartment key; room key; spare key
What part of speech is key?
Key can be a noun, an adjective, a verb or a proper noun.
How do you pronounce key?
Key is pronounced /kiː/ (UK).
What is the plural of key?
The plural of key is keys.

Words near key in the dictionary

  1. kexes
  2. kexin
  3. kexins
  4. kext
  5. kexts
  6. key
  7. key alike
  8. key art
  9. key artwork
  10. key artworks
  11. key back

Source and license

Adapted from Wiktionary: key (page history and authors); Key (page history and authors). Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws reformatted the entry and added links. Wiktionary data of 2026-09-02.

Last updated:

Pronunciation audio from Wikimedia Commons, each file under its own free license: en-uk-key.ogg, en-us-key.ogg.

Cite this entry: “key.” Word.ws, https://word.ws/key. Based on Wiktionary, CC BY-SA 4.0.