# key

> English word · Noun · IPA /kiː/ · frequency rank #788

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

## Easily confused with
- **kI** (https://plainspell.com/en/vs/key-vs-ki)
- **ky** (https://plainspell.com/en/vs/key-vs-ky)
- **ko** (https://plainspell.com/en/vs/key-vs-ko)
- **Ku** (https://plainspell.com/en/vs/key-vs-ku)
- **KS** (https://plainspell.com/en/vs/key-vs-ks)
- **KT** (https://plainspell.com/en/vs/key-vs-kt)
- **kk** (https://plainspell.com/en/vs/key-vs-kk)
- **KL** (https://plainspell.com/en/vs/key-vs-kl)
- **KP** (https://plainspell.com/en/vs/key-vs-kp)
- **KJ** (https://plainspell.com/en/vs/key-vs-kj)
- **KF** (https://plainspell.com/en/vs/key-vs-kf)
- **kid** (https://plainspell.com/en/vs/key-vs-kid)
- **Kim** (https://plainspell.com/en/vs/key-vs-kim)
- **kit** (https://plainspell.com/en/vs/key-vs-kit)
- **kin** (https://plainspell.com/en/vs/key-vs-kin)
- **KIA** (https://plainspell.com/en/vs/key-vs-kia)
- **KGB** (https://plainspell.com/en/vs/key-vs-kgb)
- **KFC** (https://plainspell.com/en/vs/key-vs-kfc)
- **kun** (https://plainspell.com/en/vs/key-vs-kun)
- **KKK** (https://plainspell.com/en/vs/key-vs-kkk)

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/key