key

/kiː/

//kiː// noun

"key" is a 3-letter English headword indexed on PlainSpell.

The verdict

“key” is in the everyday core of English, ranked #788 in English word frequency and used as a noun.

#788
frequency rank, English
3
letters
20
confusable pairs

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - An object designed to open and close a lock.

Visual similarity to commonly confused words

How many letter changes separate each confused pair (Levenshtein distance, normalized).

key vs kI
33% similar
key vs ky
67% similar
key vs ko
33% similar

Source: PlainSpell confusable corpus (Wiktionary, CC BY-SA).

Key facts for key
PropertyValue
Headwordkey
LanguageEnglish
Part of speechNoun
IPA/kiː/
Letters3
Frequency rank#788
Misspellings tracked0
Confusable pairs20
SourceWiktionary (kaikki.org)

Where “key” sits in English frequency

Every-word frequency runs from the handful of words we use constantly (left) to the long tail used once in a blue moon (right). key lands here:

#1#100#1K#10K#100K
← used constantlyrarely used →

Scale is logarithmic (each tick is 10× rarer). Source: FrequencyWords open word-frequency list.

Spelling & Dictionary Insight

The English entry for key is 3 letters long, classified as a noun, and transcribed in the International Phonetic Alphabet as /kiː/. Corpus data places it at rank #788 in overall English word frequency, putting it firmly in the everyday core of the language. Wiktionary records 34 distinct senses for this headword, so context determines which meaning a reader should apply.

key has no tracked misspelling variants, and the word's spelling is regular enough that our generator found nothing worth flagging. It also participates in 20 confusable-pair relationships, "kI", "ky", "ko", and more, where similar look or sound leads writers to substitute one word for another in context.

Etymologically, the entry records: 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”),… The correct English form is key, spelled K-E-Y.

Definition

  1. 1
    An object designed to open and close a lock.
  2. 2
    An object designed to fit between two other objects (such as a shaft and a wheel) in a mechanism and maintain their relative orientation.
  3. 3
    A crucial step or requirement.
  4. 4
    A small guide explaining symbols or terminology, especially the legend on a map or chart.
  5. 5
    A guide to the correct answers of a worksheet or test.
  6. 6
    One of several small, usually square buttons on a typewriter or computer keyboard, mostly corresponding to text characters.
  7. 7
    In musical instruments, one of the valve levers used to select notes, such as a lever opening a hole on a woodwind.
  8. 8
    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.
  9. 9
    A scale or group of pitches constituting the basis of a musical composition.
  10. 10
    A scale or group of pitches constituting the basis of a musical composition.
  11. 11
    A scale or group of pitches constituting the basis of a musical composition.
  12. 12
    A scale or group of pitches constituting the basis of a musical composition.
  13. 13
    A scale or group of pitches constituting the basis of a musical composition.
  14. 14
    The general pitch or tone of a sentence or utterance.
  15. 15
    A modification of an advertisement so as to target a particular group or demographic.
  16. 16
    An indehiscent, one-seeded fruit furnished with a wing, such as the fruit of the ash and maple; a samara.
  17. 17
    A manual electrical switching device primarily used for the transmission of Morse code.
  18. 18
    A piece of information (e.g., a password or passphrase) used to encode or decode a message or messages.
  19. 19
    A password restricting access to an IRC channel.
  20. 20
    In a relational database, a field used as an index into another table (not necessarily unique).
  21. 21
    A value that uniquely identifies an entry in a container.
  22. 22
    Any of various tools comparable to a wrench (spanner) or driver, or, in some cases, also called a wrench or driver.
  23. 23
    A series of logically organized groups of discriminating information which aims to allow the user to correctly identify a taxon.
  24. 24
    A piece of wood used as a wedge.
  25. 25
    The last board of a floor when laid down.
  26. 26
    A keystone.
  27. 27
    That part of the plastering which is forced through between the laths and holds the rest in place.
  28. 28
    A wooden wedge, driven sideways between a bullhead rail and a cast-iron chair, to keep the rail securely in position.
  29. 29
    The degree of roughness, or retention ability of a surface to have applied a liquid such as paint, or glue.
  30. 30
    The thirty-third card of the Lenormand deck.
  31. 31
    The black ink layer, especially in relation to the three color layers of cyan, magenta, and yellow. See also CMYK.
  32. 32
    A color to be masked or made transparent.
  33. 33
    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.
  34. 34
    A key position player (a tall forward or defender).

Etymology

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."

This word in other languages

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "key"?
"key" is spelled K-E-Y. The IPA pronunciation is /kiː/.
What does "key" mean?
As a noun, "key" means: An object designed to open and close a lock.
What words are commonly confused with "key"?
"key" is commonly confused with "kI", "ky", "ko". These words look or sound similar but have different meanings. PlainSpell provides detailed comparisons for each pair.
How do you pronounce "key"?
The IPA (International Phonetic Alphabet) transcription for "key" is /kiː/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What is the origin of the word "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 Koa... See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Using “key”

The practical upshot for anyone who landed here from a spell-check.

  • The one correct English spelling is K-E-Y - every other letter order is a misspelling in standard orthography.
  • Say it as /kiː/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
  • Don't mix it up with “kI” - see the side-by-side comparison. key vs kI
  • Browse more English words and confusable pairs in the same reference. English words
Data Source

Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list FrequencyWords open word-frequency list