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This article is about the letter of the alphabet. For other uses, see U (disambiguation).
Circle sheer blue 29.gif
Circle sheer blue 29.gif
Cursive script 'u' and capital 'U'
U cursiva.gif

U (named u /ˈjuː/, plural ues[1][2]) is the twenty-first letter in the ISO basic Latin alphabet and a vowel in the English alphabet.


The letter u ultimately comes from the Semitic letter Waw by way of the letter y. See the letter y for details.

During the late Middle Ages, two forms of 'v' developed, which were both used for its ancestor 'u' and modern 'v'. The pointed form 'v' was written at the beginning of a word, while a rounded form 'u' was used in the middle or end, regardless of sound. So whereas 'valor' and 'excuse' appeared as in modern printing, 'have' and 'upon' were printed 'haue' and 'vpon'. The first distinction between the letters 'u' and 'v' is recorded in a Gothic alphabet from 1386, where 'v' preceded 'u'. Printers eschewed capital 'U' into the 17th century and the distinction between the two letters was not fully accepted by the French Academy until 1762.[3]

Use in English[edit]

In English the letter is pronounced differently in different words. As an English vowel letter, it has a "long" and "short" pronunciation that are used in different contexts. Short 'u', found in closed syllables, commonly represents /ʌ/ (as in 'duck') or /ʊ/ (as in 'put'). Long 'u' commonly represents /juː/ ("long U" as in 'mule') or // (as in 'blue'). In a select few words, short 'u' may also represent /ɪ/ (as in 'business').

Additionally, the letter 'u' is used in text messaging and internet and other written slang to denote 'you', by virtue of both being pronounced /juː/.

Use in other languages[edit]

In most languages that use the Latin alphabet, 'U' represents the close back rounded vowel /u/[citation needed].

In French orthography the letter represents the close front rounded vowel(/y/); /u/ is represented by 'ou'.

In mathematics and science[edit]

The symbol 'U' is the chemical symbol for uranium.

'u' is the symbol for the atomic mass unit.

U is also the source of the mathematical symbol ∪, representing a union. It is used mainly for Venn diagrams and geometry.

It is also used as a graphic approximation of the Greek letter μ (mu) for micro- in metric measurements, as in "um" for μm (micrometer).

Related letters and other similar characters[edit]

Computing codes[edit]

Numeric character referenceUUuu
EBCDIC family228E4164A4
ASCII 1855511775
1 Also for encodings based on ASCII, including the DOS, Windows, ISO-8859 and Macintosh families of encodings.

Other representations[edit]

NATO phoneticMorse code
ICS Uniform.svgSemaphore Uniform.svg⠥
Signal flagFlag semaphoreBraille


  1. ^ "U", Oxford English Dictionary, 2nd edition (1989); Merriam-Webster's Third New International Dictionary of the English Language, Unabridged (1993)
  2. ^ Brown & Kiddle (1870) The institutes of English grammar, page 19.
    Ues is the plural of the name of the letter; the plural of the letter itself is rendered U's, Us, u's, or us.
  3. ^ Pflughaupt, Laurent (2008). Letter by Letter: An Alphabetical Miscellany. trans. Gregory Bruhn. Princeton Architectural Press. pp. 123–124. ISBN 978-1-56898-737-8. Retrieved 2009-06-21. 

External links[edit]