O

This article is about the letter of the Roman alphabet. For the letter of the Cyrillic script (О, о), see O (Cyrillic). For the letter of the Greek script (Ο ο), see Omicron. For other uses, see O (disambiguation).

Not to be confused with the number 0.

O
O o
Usage
Writing system	Latin script
Type	Alphabetic
Language of origin	Latin language
Sound values	[o] [o̞] [ɔ] [əʊ] [əʉ] [oʊ] [ɐʊ] [ɐʉ] [ɒʊ] [uː] [ʉː] [ʌ] [ɒ] [ɑ] [ø] [a] [ʕ] [w] [◌ʷ] [ʊ] [ɵ] [ə] [ɐ]
In Unicode	U+004F, U+006F
Alphabetical position	15
History
Development	Ο ο 𐌏 O o
Time period	c. 700 BCE to present
Descendants	Ö ⱺ Ø Œ Ɔ Ơ Ỏ Ꝋ ∅ º ℅
Sisters	ᴥ Ƹ ʿ О Ю Ө ע ع ܥ ࠏ ዐ ࡘ ჺ Ո ո Օ օ ᱳ ᱜ ᱣ
Other
Associated graphs	o(x)
Writing direction	Left-to-right

O (minuscule: 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 /ˈoʊ/ ^ⓘ), plural oes.

Name

In English, the name of the letter is the "long O" sound, pronounced /ˈoʊ/. 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

History

Egyptian	Phoenician Ayin	Western Greek Omicron	Etruscan O	Latin O

Its graphic form has remained fairly constant from Phoenician times until today. The name of the Phoenician letter was ʿeyn, meaning "eye", and 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.

The use of this Phoenician letter for a vowel sound is due to the early Greek alphabets, which adopted the letter "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"). The Greek omicron gave rise to the corresponding Cyrillic letter O.

Late Renaissance or early Baroque design of an O, from 1627

Use in writing systems

Pronunciation of ⟨o⟩ by language

Orthography	Phonemes
Catalan	/ɔ/, /o/, /u/, /w/
Standard Chinese (Pinyin)	/ə/, /u/
Czech	/ɔ/
Danish	/ɔ/, /o/, /oː/
Dutch	/ɔ/, /oː/, /ə/
English	/ɒ/, /oʊ/, /ə/, /ɔː/, /aɪə/
French	/o/, /ɔ/
German	/ɔ/, /oː/, /o/
Irish	/ɔ/, /ə/
Italian	/o/, /ɔ/
Malagasy	/u/
Malay	/ɔ/
Norwegian	/ɔ/, /ʊ/, /oː/, /uː/
Occitan	/u/
Polish	/ɔ/
Portuguese	/ɔ/, /o/, /u/, /w/
Spanish	/o/
Slovak	/ɔ/
Swedish	/ɔ/, /oː/, /uː/
Turkish	/o/

English

The letter ⟨o⟩ is the fourth most common letter in the English alphabet. 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 /oʊ/ (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].

Common digraphs include ⟨oo⟩, which represents either /uː/, /ʊ/ or /ʌ/; ⟨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.

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