O

This article is about the letter. For other uses, see O (disambiguation).

Basic Latin alphabet
Aa	Bb	Cc	Dd
Ee	Ff	Gg	Hh
Ii	Jj	Kk	Ll	Mm	Nn
Oo	Pp	Qq	Rr	Ss	Tt
Uu	Vv	Ww	Xx	Yy	Zz

O ( /ˈoʊ/; named o, plural oes)^[1] is the fifteenth letter and a vowel in the basic modern Latin alphabet. The letter was derived from the Semitic `Ayin (eye), which represented a consonant, probably [ʕ], the sound represented by the Arabic letter ع called `Ayn. This Semitic letter in its original form seems to have been inspired by a similar Egyptian hieroglyph for "eye". The Greeks are thought to have come up with the innovation of vowel characters, and lacking a pharyngeal consonant, employed this letter as the Greek O to represent the vowel /o/, a sound it maintained in Etruscan and Latin. In Greek, a variation of the form later came to distinguish this long sound (Omega, meaning "large O") from the short o (Omicron, meaning "small o").

Its graphic form has also remained fairly constant from Phoenician times until today. Indeed, even alphabets constructed "from scratch", i.e. not derived from Semitic, usually have similar forms to represent this sound—for example the creators of the Afaka and Ol Chiki scripts, each invented in different parts of the world in the last century, both attributed their vowels for 'O' to the shape of the mouth when making this sound.

Usage

The letter O is the fourth most common letter in English language. O is most commonly associated with the close-mid back rounded vowel [o] in many languages. This form is colloquially termed the "long o" as in boat in English, but it is actually most often a diphthong /oʊ/ (realized dialectically anywhere from [o] to [əʊ]). In English there is a "short O" as in fox, which also has several pronunciations. In most dialects of British English, it is an open back rounded vowel [ɒ]; in American English, it is most commonly unrounded back to central vowel [ɑː] to [a].

Common digraphs include ⟨oo⟩, which represents either /uː/, /ʊ/ or /ʌ/; ⟨oi⟩ which typically represents the diphthong /ɔɪ/, like the pronunciation of ⟨oi⟩ in "boil"; and ⟨ao⟩, ⟨oe⟩, and ⟨ou⟩ which represent a variety of pronunciations depending on context and etymology.

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.

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

Related letters and other similar characters

• Ο ο : Greek letter Omicron
• О о : Cyrillic letter O
• 0 : digit zero, which is often confused with the letter O
• Ø ø : Latin letter Ø
• ∅ : empty set symbol

Computing codes

character	O		o
Unicode name	LATIN CAPITAL LETTER O		LATIN SMALL LETTER O
character encoding	decimal	hex	decimal	hex
Unicode	79	004F	111	006F
UTF-8	79	4F	111	6F
Numeric character reference	O	O	o	o
EBCDIC family	214	D6	150	96
ASCII 1	79	4F	111	6F

¹ and all encodings based on ASCII, including the DOS, Windows, ISO-8859 and Macintosh families of encodings.

Other representations

NATO phonetic	Morse code
Oscar	–––

Signal flag	Flag semaphore	Braille

References

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 Os, O's, os, o's.

External links

• Media related to O at Wikimedia Commons
• The Wiktionary definition of O
• The Wiktionary definition of o

The ISO basic Latin alphabetv · d · e
Aa	Bb	Cc	Dd	Ee	Ff	Gg	Hh	Ii	Jj	Kk	Ll	Mm	Nn	Oo	Pp	Qq	Rr	Ss	Tt	Uu	Vv	Ww	Xx	Yy	Zz
Letter O with diacritics
Óó	Òò	Ŏŏ	Ôô	Ốố	Ồồ	Ỗỗ	Ổổ	Ǒǒ	Öö	Ȫȫ	Őő	Õõ	Ṍṍ	Ṏṏ	Ȭȭ	Ȯȯ	O͘o͘	Ȱȱ	Øø	Ǿǿ	Ǫǫ	Ǭǭ	Ōō	Ṓṓ	Ṑṑ
Ỏỏ	Ȍȍ	Ȏȏ	Ơơ	Ớớ	Ờờ	Ỡỡ	Ởở	Ợợ	Ọọ	Ộộ	Ɵɵ	Ɔɔ	ⱺ
Related
History Palaeography Derivations Diacritics Punctuation Numerals Unicode List of letters ISO/IEC 646