is the eleventh letter
of the modern English alphabet
and the ISO basic Latin alphabet
. Its name in English is kay
(pronounced ), plural kays
. The letter K usually represents the voiceless velar plosive
The letter K comes from the Greek letter Κ (kappa
), which was taken from the Semitic kaph
, the symbol for an open hand. This, in turn, was likely adapted by Semitic tribes who had lived in Egypt from the hieroglyph for "hand" representing /ḏ/
in the Egyptian word for hand, ⟨ḏ-r-t
⟩ (likely pronounced in Old Egyptian
). The Semites evidently assigned it the sound value instead, because their word for hand started with that sound.
In the earliest Latin
inscriptions, the letters C, K and Q were all used to represent the sounds and (which were not differentiated in writing). Of these, Q was used before a rounded vowel (e.g. 'ego'), K before /a/ (e.g. 'calendis'), and C elsewhere. Later, the use of C and its variant G replaced most usages of K and Q. K survived only in a few fossilized forms such as Kalendae
, "the calends
words were taken into Latin, the Kappa was transliterated as a C. Loanwords from other alphabets with the sound were also transliterated with C. Hence, the Romance languages
generally use C, in imitating Classical Latin's practice, and have K only in later loanwords from other language groups. The Celtic languages
also tended to use C instead of K, and this influence carried over into Old English
Use in modern writing systems
Today, English is the only Germanic language
to productively use "hard" (outside the digraph
) rather than (although Dutch
uses it in loan words of Latin origin
, and the pronunciation of these words follows the same hard/soft distinction as in English).
The Silent k and g|letter is silent
at the start of an English word when it comes before the letter , as in the words "knight," "knife," "knot," "know," and "knee".
, and Z
, the letter K is not used very frequently in English. It is the fifth least frequently used letter
in the English language, with a frequency in words of about 0.8%.
In the International System of Units (SI)
, the SI prefix
for one thousand is kilo-
, officially abbreviated as k
: for example, prefixed to metre
or its abbreviation m
signifies a thousand metres. As such, people occasionally represent numbers in a non-standard notation by replacing the last three zeros of the general numeral with K
, as in 30K for 30,000.
In most languages where it is employed, this letter represents the sound (with or without aspiration
) or some similar sound.
The International Phonetic Alphabet
uses for the voiceless velar plosive
Ancestors, descendants and siblings
𐤊 : Semitic letter Kaph, from which the following symbols originally derive
Κ κ/ϰ : Greek letter Kappa, from which K derives
К к : Cyrillic letter Ka, also derived from Kappa
K with diacritics: Ƙ ƙ Ꝁ ꝁ Ḱ ḱ Ǩ ǩ Ḳ ḳ Ķ ķ ᶄ Ⱪ ⱪ Ḵ ḵ
Ꞣ and ꞣ were used in Latvian orthography before 1921
The Uralic Phonetic Alphabet uses various forms of the letter K:
ₖ : Subscript small k was used in the Uralic Phonetic Alphabet prior to its formal standardization in 1902
Ʞ ʞ : Turned capital and small k were used in transcriptions of the Dakota language in publications of the American Board of Ethnology in the late 19th century. Turned small k was also used for a velar click in the International Phonetic Alphabet but its use was withdrawn in 1970.
Ligatures and abbreviations
₭ : Lao kip
Ꝃ ꝃ, Ꝅ ꝅ, Ꞣ ꞣ : Various forms of K were used for medieval scribal abbreviations
Computing codes :
"K" replacing "C" in satiric misspelling.
K is the unit symbol for the kelvin, used to measure thermodynamic temperature.
K is the chemical symbol for the element potassium (K is an abbreviation of kalium, the Latin name for potassium).
Unit prefix k, meaning 1000 times.
Josef K is the name of the principal character in Franz Kafka's novel The Trial.
In chess notation, the letter K represents the King (WK for White King, BK for Black King).
In baseball scoring, the letter K is used to represent a strikeout. A forwards oriented K represents a "strikeout swinging"; a backwards oriented K (9px) represents a "strikeout looking".
As abbreviation for OK, often used in emails and short text messages.
K is used as a slang term for Ketamine among recreational drug users.
In the CMYK color model, K represents black ink.
In International Morse code it is used to mean "over".
In fracture mechanics, K is used to represent the stress intensity factor.
In physics, k usually stands for Boltzmann's constant
K is used colloquially to mean kilometre (as in "a 10K run").
When expressing amounts of money, $20K means twenty thousand dollars.
In the United Kingdom under the old system (before 2001), a licence plate that begins with "K" for example "K123 XYZ" would correspond to a vehicle registered between August 1, 1992 and July 31, 1993. Again under the old system, a licence plate that ends with "K" for example "ABC 123K" would correspond to a vehicle that was registered between August 1, 1971 and July 31, 1972.