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O o
Writing systemLatin script
Language of originLatin language
Phonetic usage[o]
Unicode codepointU+004F, U+006F
Alphabetical position15
Time period~-700 to present
Descendants • Ö
 • Ø
 • Œ
 • Ɔ
 • Ơ
 • º
 • ℅

Ո ո
Օ օ

Other letters commonly used witho(x)
Writing directionLeft-to-Right
This article contains phonetic transcriptions in the International Phonetic Alphabet (IPA). For an introductory guide on IPA symbols, see Help:IPA. For the distinction between [ ], / / and  , see IPA § Brackets and transcription delimiters.

O, or o, is the fifteenth letter and the fourth vowel letter of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is o (pronounced /ˈ/), plural oes.[1]


In English, the name of the letter is the "long O" sound, pronounced /ˈ/. In most other languages, its name matches the letter's pronunciation in open syllables.

Pronunciation of the name of the letter ⟨o⟩ in European languages


Egyptian Phoenician
Western Greek
Egyptian Hieroglyph describing an eye Latin O
Late Renaissance or early Baroque design of an O, from 1627

Its graphic form has remained fairly constant from Phoenician times until today. The name of the Phoenician letter was ʿeyn, meaning "eye", and indeed its shape originates simply as a drawing of a human eye (possibly inspired by the corresponding Egyptian hieroglyph, cf. Proto-Sinaitic script). Its original sound value was that of a consonant, probably [ʕ], the sound represented by the cognate Arabic letter ع ʿayn.[2]

The use of this Phoenician letter for a vowel sound is due to the early Greek alphabets, which adopted the letter of O "omicron" to represent the vowel /o/. The letter was adopted with the value in the Old Italic alphabets, including the early Latin alphabet. In Greek, a variation of the form later came to differentiate this long sound (Omega, meaning "large O") from the short o (Omicron, meaning "small o"). Greek omicron gave rise to the corresponding Cyrillic letter O.[2][3]

Use in writing systems

Pronunciation summary
Languages in italics are not usually written using the Latin alphabet
Language Dialect(s) Pronunciation (IPA) Environment Notes
Mandarin Chinese Standard /ə/, /u/ Pinyin romanization
English /ɒ/, /oʊ/, /ə/ See English orthography
/ɔː/, /aɪə/ Before ⟨r⟩
French /o/, /ɔ/ See French orthography
German /ɔ/, //, /o/ See German orthography
Portuguese /o/, /ɔ/, /u/ See Portuguese orthography
/w/ Before vowels
Spanish /o/
Turkish /o/


The letter ⟨o⟩ is the fourth most common letter in the English alphabet.[4] Like the other English vowel letters, it has associated "long" and "short" pronunciations. The "long" ⟨o⟩ as in boat is actually most often a diphthong // (realized dialectically anywhere from [o] to [əʊ]). In English there is also a "short" ⟨o⟩ as in fox, /ɒ/, which sounds slightly different in different dialects. In most dialects of British English, it is either an open-mid back rounded vowel [ɔ] or an open back rounded vowel [ɒ]; in American English, it is most commonly an unrounded back [ɑ] to a central vowel [a].[5]

Common digraphs include ⟨oo⟩, which represents either // or /ʊ/; ⟨oi⟩ or ⟨oy⟩, which typically represents the diphthong /ɔɪ/, and ⟨ao⟩, ⟨oe⟩, and ⟨ou⟩ which represent a variety of pronunciations depending on context and etymology.[5]

In other contexts, especially before a letter with a minim, ⟨o⟩ may represent the sound /ʌ/, as in 'son' or 'love'. It can also represent the semivowel /w/ as in choir or quinoa.[citation needed]

"O" in isolation is a word, also spelled "oh" and pronounced /oʊ/. Before a noun, usually capitalized, it indicates direct address (the vocative case), as in the titles to O Canada or O Captain! My Captain! or in certain verses of the Bible.[6]

Other languages

⟨o⟩ is commonly associated with the open-mid back rounded vowel [ɔ], mid back rounded vowel [o̞] or close-mid back rounded vowel [o] in many languages. Other languages use ⟨o⟩ for various values, usually back vowels which are at least partly open. Derived letters such as ö and ø have been created for the alphabets of some languages to distinguish values that were not present in Latin and Greek, particularly rounded front vowels.[citation needed]

Other systems

In the International Phonetic Alphabet, o represents the close-mid back rounded vowel.[7]

Other uses

Main article: O (disambiguation)

Related characters

See also: circle symbol

Descendants and related characters in the Latin alphabet

Derived signs, symbols and abbreviations

Ancestors and siblings in other alphabets

Other representations


Character information
Preview O o
Encodings decimal hex dec hex dec hex dec hex
Unicode 79 U+004F 111 U+006F 65327 U+FF2F 65359 U+FF4F
UTF-8 79 4F 111 6F 239 188 175 EF BC AF 239 189 143 EF BD 8F
Numeric character reference O O o o O O o o
EBCDIC family 214 D6 150 96
ASCII g1 79 4F 111 6F
1 Also for encodings based on ASCII, including the DOS, Windows, ISO-8859 and Macintosh families of encodings.[citation needed]


NATO phonetic Morse code
  ▄▄▄ ▄▄▄ ▄▄▄ 

Signal flag Flag semaphore American manual alphabet (ASL fingerspelling) British manual alphabet (BSL fingerspelling) Braille dots-135
Unified English Braille

See also


  1. ^ "O" Oxford English Dictionary, 2nd edition (1989);Chambers-Happap, "oes" op. cit. Oes is the plural of the name of the letter. The plural of the letter itself is rendered Os, O's, os, o's.
  2. ^ a b "Evolution of Alphabets". Retrieved 2024-01-03.
  3. ^ "Cyrillic script". Retrieved 2024-01-03.
  4. ^ "Frequency Table".
  5. ^ a b "International Phonetic Alphabet for American English - IPA Chart". Retrieved 2024-01-03.
  6. ^ "Quick search: "o lord"". Retrieved 2013-12-05.
  7. ^ "IPA Chart with Sounds – International Phonetic Alphabet Sounds". Retrieved 2023-10-22.
  8. ^ Constable, Peter (2004-04-19). "L2/04-132 Proposal to add additional phonetic characters to the UCS" (PDF).
  9. ^ a b Everson, Michael; Baker, Peter; Emiliano, António; Grammel, Florian; Haugen, Odd Einar; Luft, Diana; Pedro, Susana; Schumacher, Gerd; Stötzner, Andreas (2006-01-30). "L2/06-027: Proposal to add Medievalist characters to the UCS" (PDF).
  10. ^ Bunčić, Daniel (2021-01-12). "L2/21-039: Proposal to include the letter 'Old Polish O'" (PDF).
  11. ^ Lemonen, Therese; Ruppel, Klaas; Kolehmainen, Erkki I.; Sandström, Caroline (2006-01-26). "L2/06-036: Proposal to encode characters for Ordbok över Finlands svenska folkmål in the UCS" (PDF).
  12. ^ Miller, Kirk; Ashby, Michael (2020-11-08). "L2/20-252R: Unicode request for IPA modifier-letters (a), pulmonic" (PDF).
  13. ^ Everson, Michael; et al. (2002-03-20). "L2/02-141: Uralic Phonetic Alphabet characters for the UCS" (PDF).
  14. ^ Everson, Michael; Dicklberger, Alois; Pentzlin, Karl; Wandl-Vogt, Eveline (2011-06-02). "L2/11-202: Revised proposal to encode "Teuthonista" phonetic characters in the UCS" (PDF).
  15. ^ Anderson, Deborah; Everson, Michael (2004-06-07). "L2/04-191: Proposal to encode six Indo-Europeanist phonetic characters in the UCS" (PDF).
  16. ^ Miller, Kirk (2020-07-11). "L2/20-125R: Unicode request for expected IPA retroflex letters and similar letters with hooks" (PDF).
  17. ^ Anderson, Deborah (2020-12-07). "L2/21-021: Reference doc numbers for L2/20-266R "Consolidated code chart of proposed phonetic characters" and IPA etc. code point and name changes" (PDF).
  18. ^ "Earliest Uses of Symbols of Set Theory and Logic".
  19. ^ "Script (or Calligraphic)". Retrieved 2024-01-03.