{{Short description|Fifteenth letter of the Latin alphabet}} {{About|the letter of the Roman alphabet|the letter of the [[Cyrillic script]] (О, о)|O (Cyrillic)|the letter of the [[Greek script]] (Ο ο) |Omicron|other uses}} {{Distinguish|text=the number [[0]]}} {{pp-pc}} {{pp-move|small=yes}} {{Use mdy dates|date=July 2024}} {{Technical reasons|:O|the keyboard symbol|List of emoticons}} {{refimprove|date=November 2022}} {{Infobox grapheme |name=O |letter=O o |script=[[Latin script]] |type=[[Alphabet]] |typedesc=ic |language=[[Latin ]]language |phonemes={{flex list|{{IPAblink|o}}|{{IPAblink|o̞}}|{{IPAblink|ɔ}}|{{IPA|[əʊ]}}|{{IPA|[əʉ]}}|{{IPA|[oʊ]}}|{{IPA|[ɐʊ]}}|{{IPA|[ɐʉ]}}|{{IPA|[ɒʊ]}}|{{IPAblink|uː}}|{{IPAblink|ʉː}}|{{IPAblink|ʌ}}|{{IPAblink|ɒ}}|{{IPAblink|ɑ}}|{{IPAblink|ø}}|{{IPAblink|a}}|{{IPAblink|ʕ}}|{{IPAblink|w}}|{{IPAblink|ʷ|◌ʷ}}|{{IPAblink|ʊ}}|{{IPAblink|ɵ}}|{{IPAblink|ə}}|{{IPAblink|ɐ}}}} |unicode=U+004F, U+006F |alphanumber=15 |number= |fam1=<hiero>D4</hiero> |fam2=[[File:Proto-semiticO-01.svg|class=skin-invert-image|20px|Proto-sinaitic ʿayin]] |fam3=[[File:Protoayin.svg|class=skin-invert-image|20px]] |fam4=[[File:Phoenician ayin.svg|class=skin-invert-image|20px|Phoenician Ayin]] |fam5=[[Omicron|Ο ο]] |fam6=[[𐌏]] |usageperiod= {{circa}} 700 BCE to present |children={{flex list|[[Ö]]|[[ⱺ]]|[[Ø]]|[[Œ]]|[[Ɔ]]|[[Ơ]]|[[Ỏ]]|[[Ꝋ]]|[[∅]]|[[º]]|{{not a typo|℅}}}} |sisters={{flex list|[[ᴥ]]|[[Ƹ]]|[[ʿ]]|[[О]]|[[Ю]]|[[Ө]]|[[Ayin|ע]]|[[Ayin|ع]]|[[Ayin|ܥ]]|[[ࠏ]]|[[ዐ]]|[[ࡘ]]|[[ჺ]]|[[wikt:Ո|Ո]] [[wikt:ո|ո]]|[[wikt:Օ|Օ]] [[wikt:օ|օ]]|[[ᱳ]]|[[Ol Chiki script|ᱜ ᱣ]]}} |equivalents= |associates=[[List of Latin-script digraphs#O|o(x)]] |direction=Left-to-right |image=File:Latin_letter_O.svg |imageclass=skin-invert-image }} {{Latin letter info|o}}
'''O''' ([[Letter case|minuscule]]: '''o''') is the fifteenth [[Letter (alphabet)|letter]] and the fourth [[vowel letter]] of the [[Latin alphabet]], used in the [[English alphabet|modern English alphabet]], the alphabets of other western European languages and others worldwide.<!--it's not necessarily the 4th vowel in Basic Latin, as <j> is sometimes used as a vowel.--> Its name in English is [[English alphabet#Letter names|''o'']] (pronounced {{IPAc-en|'|oʊ|audio=LL-Q1860 (eng)-Flame, not lame-O.wav}}), plural [[English alphabet#Letter names|''oes'']].<ref>"O" ''Oxford English Dictionary,'' 2nd edition (1989);[http://www.chambersharrap.co.uk/chambers/features/chref/chref.py/main?query=o&title=21st ''Chambers-Happap''], "oes" ''op. cit.'' ''Oes'' is the plural of the name of the letter. The plural of the letter itself is rendered ''O''s, O's, ''o''s, o's.</ref> <!--|[[File:Proto-semiticO-01.svg|class=skin-invert-image]] |[[File:PhoenicianO-01.svg|class=skin-invert-image|65px]] |[[File:EtruscanO-01.svg|class=skin-invert-image|65px]] |[[File:Omicron uc lc.svg|class=skin-invert-image|65px]] |}-->
==Name== In English, the name of the letter is the "long O" sound, pronounced {{IPAc-en|'|oʊ}}. In most other languages, its name matches the letter's pronunciation in [[open syllable]]s. [[File:Pronunciation of the name of the letter ⟨o⟩ in European languages.png|thumb|Pronunciation of the name of the letter {{angbr|o}} in European languages|upright=1.5|center|class=skin-invert-image]]
==History== {| class="wikitable skin-invert-image" ! [[Egyptian hieroglyphs|Egyptian]] ! [[Phoenician alphabet|Phoenician]]<br/>[[Ayin]] ! [[Western Greek alphabet|Western Greek]]<br/>[[Omicron]] ! [[Etruscan language|Etruscan]]<br>O ! [[Latin]]<br/>O |--- align=center |[[File:Hieroglyph D4.svg|alt=Egyptian Hieroglyph describing an eye|45px]] |[[File:PhoenicianO-01.svg|30px]] |[[File:Greek Omicron 04.svg|30px]] |[[File:EtruscanO-01.svg|25px]] |[[File:Capitalis monumentalis O.SVG|x30px|Latin O]] |}
Its graphic form has remained fairly constant from [[Phoenician alphabet|Phoenician]] times until today. The name of the Phoenician letter was ''[[Ayin|ʿeyn]]'', meaning "eye", and its shape originates simply as a drawing of a human eye (possibly inspired by the corresponding [[Egyptian hieroglyphs|Egyptian hieroglyph]], {{Cf.}}[[Proto-Sinaitic script]]). Its original sound value was that of a consonant, probably {{IPAblink|ʕ}}, the sound represented by the cognate [[Arabic alphabet|Arabic letter]] [[ع|ع ''ʿayn'']].<ref name=":0">{{Cite web |title=Evolution of Alphabets |url=https://webspace.ship.edu/cgboer/evolalpha.html |access-date=2024-01-03 |website=webspace.ship.edu}}</ref>
The use of this Phoenician letter for a vowel sound is due to the early [[Greek alphabet]]s, which adopted the letter "[[omicron]]" to represent the vowel {{IPA|/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 [[O (Cyrillic)|Cyrillic letter O]].<ref name=":0" />
[[File:Newes ABC Buchlein MET DP855603.jpg|thumb|center|180px|Late [[Renaissance]] or early [[Baroque]] design of an O, from 1627]]
==Use in writing systems== {| class="wikitable mw-collapsible" |+ Pronunciation of {{angbr|o}} by language ! [[Orthography]] ! [[Phoneme|Phonemes]] |- ! [[Catalan orthography|Catalan]] | {{IPAslink|ɔ}}, {{IPAslink|o}}, {{IPAslink|u}}, {{IPAslink|w}} |- ! {{nwr|[[Standard Chinese]] ([[Pinyin]])}} | {{IPAslink|ə}}, {{IPAslink|u}} |- ! [[Czech orthography|Czech]] | {{IPAslink|ɔ}} |- ! [[Danish orthography|Danish]] | {{IPAslink|ɒ|ɔ}}, {{IPAslink|o}}, {{IPAslink|oː}} |- ! [[Dutch orthography|Dutch]] | {{IPAslink|ɔ}}, {{IPAslink|oː}}, {{IPAslink|ə}} |- ! [[English orthography|English]] | {{IPAslink|ɒ}}, {{IPA|/oʊ/}}, {{IPAslink|ə}}, {{IPAslink|ɔː}}, {{IPA|/aɪə/}} |- ! [[French orthography|French]] | {{IPAslink|o}}, {{IPAslink|ɔ}} |- ! [[German orthography|German]] | {{IPAslink|ɔ}}, {{IPAslink|oː}}, {{IPAslink|o}} |- ! [[Irish orthography|Irish]] | {{IPAslink|ɔ}}, {{IPAslink|ə}} |- ! [[Italian orthography|Italian]] | {{IPAslink|o}}, {{IPAslink|ɔ}} |- ! [[Malagasy language|Malagasy]] | {{IPAslink|u}} |- ! [[Malay orthography|Malay]] | {{IPAslink|ɔ}} |- ! [[Norwegian orthography|Norwegian]] | {{IPAslink|ɔ}}, {{IPAslink|ʊ}}, {{IPAslink|oː}}, {{IPAslink|uː}} |- ! [[Occitan orthography|Occitan]] | {{IPAslink|u}} |- ! [[Polish orthography|Polish]] | {{IPAslink|ɔ}} |- ! [[Portuguese orthography|Portuguese]] | {{IPAslink|ɔ}}, {{IPAslink|o}}, {{IPAslink|u}}, {{IPAslink|w}} |- ! [[Spanish language|Spanish]] | {{IPAslink|o}} |- ! [[Slovak orthography|Slovak]] | {{IPAslink|ɔ}} |- ! [[Swedish orthography|Swedish]] | {{IPAslink|ɔ}}, {{IPAslink|oː}}, {{IPAslink|uː}} |- ! [[Turkish alphabet|Turkish]] | {{IPAslink|o}} |}
===English=== The letter {{angbr|o}} is the fourth [[Letter frequency|most common letter]] in the [[English alphabet]].<ref>{{cite web|url=https://pi.math.cornell.edu/~mec/2003-2004/cryptography/subs/frequencies.html|title=Frequency Table|website=www.math.cornell.edu}}</ref> Like the other English vowel letters, it has associated "long" and "short" pronunciations. The "long" {{angbr|o}} as in ''boat'' is actually most often a [[diphthong]] {{IPAc-en|oʊ}} (realized dialectically anywhere from {{IPA|[o]}} to {{IPA|[əʊ]}}). In English, there is also a "short" {{angbr|o}} as in ''fox'', {{IPAc-en|ɒ}}, which sounds slightly different in different dialects. In most dialects of [[British English]], it is either an [[open-mid back rounded vowel]] {{IPA|[ɔ]}} or an [[open back rounded vowel]] {{IPA|[ɒ]}}; in [[American English]], it is most commonly an unrounded back {{IPA|[ɑ]}} to a central vowel {{IPA|[a]}}.<ref name=":1">{{Cite web |title=International Phonetic Alphabet for American English - IPA Chart |url=https://easypronunciation.com/en/american-english-pronunciation-ipa-chart |access-date=2024-01-03 |website=easypronunciation.com}}</ref>
Common [[Digraph (orthography)|digraphs]] include {{angbr|oo}}, which represents either {{IPAc-en|uː}}, {{IPAc-en|ʊ}} or {{IPAc-en|ʌ}}; {{angbr|oi}} or {{angbr|oy}}, which typically represents the diphthong {{IPAc-en|ɔɪ}}, and {{angbr|ao}}, {{angbr|oe}}, and {{angbr|ou}} which represent a variety of pronunciations depending on context and etymology.<ref name=":1" />
In other contexts, especially before a letter with a [[minim (palaeography)|minim]], {{angbr|o}} may represent the sound {{IPAc-en|ʌ}}, as in 'son' or 'love'. It can also represent the [[semivowel]] {{IPAc-en|w}}, as in ''choir'' or ''quinoa.''<ref>{{Cite book |last=Millward |first=C.M |title=History of the English Language |date=1988-12-01 |publisher=Thomson Learning |isbn=0030594316 |publication-date=1988-12-01 |pages={{!}}pages=137-138}}</ref>
"O" in isolation is a word, also spelled "oh" and pronounced {{IPA|/oʊ/}}. Before a noun, usually capitalized, it indicates a [[noun of address]], as in the titles "[[O Canada]]" or "[[O Captain! My Captain!]]" or in certain verses of the [[Bible]].<ref>{{cite web|url=http://www.biblegateway.com/quicksearch/?quicksearch=%22o+lord%22&qs_version=KJV |title=Quick search: "o lord" |access-date=2013-12-05}}</ref>
===Other languages=== {{angbr|o}} is commonly associated with the [[open-mid back rounded vowel]] {{IPA|[ɔ]}}, [[mid back rounded vowel]] {{IPA|[o̞]}} or [[close-mid back rounded vowel]] {{IPA|[o]}} in many languages. Other languages use {{angbr|o}} for various values, usually back vowels which are at least partly open. Derived letters such as {{angbr|[[ö]]}} and {{angbr|[[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.<ref>{{Cite web |title=Latin Script |url=https://www.britannica.com/topic/Latin-alphabet |access-date=2026-03-13}}</ref>
===Other systems=== In the [[International Phonetic Alphabet]], {{angbr IPA|o}} represents the [[close-mid back rounded vowel]].<ref>{{Cite web |title=IPA Chart with Sounds – International Phonetic Alphabet Sounds |url=https://www.internationalphoneticalphabet.org/ipa-sounds/ipa-chart-with-sounds/ |access-date=2023-10-22 |website=www.internationalphoneticalphabet.org}}</ref>
== Other uses == {{main article|O (disambiguation)}} * [[Oxygen]], symbol O, a chemical element
==Related characters== {{see also|Circle symbol (disambiguation){{!}}circle symbol}} <!-- Please only list characters (symbols in a writing system, but not just convenience code points in Unicode) that are actually related in terms of origin to the letter that is the topic of this article. Characters that merely look subjectively similar need not apply. See https://en.wikipedia.org/wiki/Wikipedia:Verifiability and https://en.wikipedia.org/wiki/Wikipedia:Identifying_reliable_sources before adding more. -->
===Descendants and related characters in the Latin alphabet=== {{Flowlist| * Œ œ : Latin [[Œ|''OE'']] ligature * O with [[diacritic]]s: [[Ø|Ø ø]] [[Ǿ|Ǿ ǿ]] [[Ö|Ö ö]] [[Ȫ|Ȫ ȫ]] [[Ó|Ó ó]] [[Ò|Ò ò]] [[circumflex|Ô ô]] [[Ố|Ố ố]] [[Ồ|Ồ ồ]] [[Ổ|Ổ ổ]] [[Ỗ|Ỗ ỗ]] [[Ộ|Ộ ộ]] [[caron|Ǒ ǒ]] [[double acute accent|Ő ő]] [[breve|Ŏ ŏ]] [[Ȏ|Ȏ ȏ]] [[Dot (diacritic)|Ȯ ȯ]] [[Ȱ|Ȱ ȱ]] [[Dot (diacritic)|Ọ ọ]] [[Ɵ|Ɵ ɵ]] [[ᶱ]]<ref>{{cite web|url=https://www.unicode.org/L2/L2004/04132-n2740-phonetic.pdf|title=L2/04-132 Proposal to add additional phonetic characters to the UCS|date=2004-04-19|first=Peter|last=Constable}}</ref> [[Ơ|Ơ ơ]] [[Ớ|Ớ ớ]] [[Ờ|Ờ ờ]] [[Ỡ|Ỡ ỡ]] [[Ợ|Ợ ợ]] [[Ở|Ở ở]] [[Hook above|Ỏ ỏ]] [[Macron (diacritic)|Ō ō]] [[Ṓ|Ṓ ṓ]] [[Ṑ|Ṑ ṑ]] [[Õ|Õ õ]] [[Ȭ|Ȭ ȭ]] [[Ṍ|Ṍ ṍ]] [[Ṏ|Ṏ ṏ]] [[ogonek|Ǫ ǫ]] [[double grave accent|Ȍ ȍ]] O̩ o̩ Ó̩ ó̩ Ò̩ ò̩ [[Ǭ|Ǭ ǭ]] O͍ o͍ * [[Ꝍ|Ꝍ ꝍ]] : O with loop was used in some [[North Germanic languages|medieval Nordic]] [[Orthography|orthographies]]<ref name="unicode2006">{{cite web|url=https://www.unicode.org/L2/L2006/06027-n3027-medieval.pdf|title=L2/06-027: Proposal to add Medievalist characters to the UCS|date=2006-01-30|first1=Michael|last1=Everson|first2=Peter|last2=Baker|first3=António|last3=Emiliano|first4=Florian|last4=Grammel|first5=Odd Einar|last5=Haugen|first6=Diana|last6=Luft|first7=Susana|last7=Pedro|first8=Gerd|last8=Schumacher|first9=Andreas|last9=Stötzner}}</ref> * Ꟁ ꟁ : [[Old Polish]] O<ref>{{Cite web|title=L2/21-039: Proposal to include the letter 'Old Polish O'|url=https://www.unicode.org/L2/L2021/21039-old-polish-o.pdf|date=2021-01-12|first=Daniel|last=Bunčić}}</ref> * ⱺ : Small o with low ring inside is used in the [[Swedish Dialect Alphabet]]<ref>{{cite web|url=https://www.unicode.org/L2/L2006/06036-lma-proposal.pdf|title=L2/06-036: Proposal to encode characters for Ordbok över Finlands svenska folkmål in the UCS|date=2006-01-26|first1=Therese|last1=Lemonen|first2=Klaas|last2=Ruppel|first3=Erkki I.|last3=Kolehmainen|first4=Caroline|last4=Sandström}}</ref> * [[International Phonetic Alphabet|IPA]]-specific symbols related to O: {{IPA link|ɔ}} * [[International Phonetic Alphabet#Superscript IPA|IPA superscript letters]]:<ref>{{Cite web|title=L2/20-252R: Unicode request for IPA modifier-letters (a), pulmonic|url=https://www.unicode.org/L2/L2020/20252r-mod-ipa-a.pdf|date=2020-11-08|first1=Kirk|last1=Miller|first2=Michael|last2=Ashby}}</ref> 𐞢 𐞣 * [[Uralic Phonetic Alphabet]]-specific symbols related to O:<ref>{{cite web|url=https://www.unicode.org/L2/L2002/02141-n2419-uralic-phonetic.pdf|title=L2/02-141: Uralic Phonetic Alphabet characters for the UCS|date=2002-03-20|first1=Michael|last1=Everson|author-link1=Michael Everson|display-authors=etal}}</ref> ** {{Unichar|1D0F|LATIN LETTER SMALL CAPITAL O}} ** {{Unichar|1D3C|MODIFIER LETTER CAPITAL O}} ** {{Unichar|1D52|MODIFIER LETTER SMALL O}} ** {{Unichar|1D11|LATIN SMALL LETTER SIDEWAYS O}} ** {{Unichar|1D13|LATIN SMALL LETTER SIDEWAYS O WITH STROKE}} ** {{Unichar|1D16|LATIN SMALL LETTER TOP HALF O}} ** {{Unichar|1D17|LATIN SMALL LETTER BOTTOM HALF O}} ** {{Unichar|1D54|MODIFIER LETTER SMALL TOP HALF O}} ** {{Unichar|1D55|MODIFIER LETTER SMALL BOTTOM HALF O}} * [[Teuthonista]] phonetic transcription-specific symbols related to O:<ref>{{cite web|url=https://www.unicode.org/L2/L2011/11202-n4081-teuthonista.pdf|title=L2/11-202: Revised proposal to encode "Teuthonista" phonetic characters in the UCS|date=2011-06-02|first1=Michael|last1=Everson|first2=Alois|last2=Dicklberger|first3=Karl|last3=Pentzlin|first4=Eveline|last4=Wandl-Vogt}}</ref> ** {{Unichar|AB3D|LATIN SMALL LETTER BLACKLETTER O}} ** {{Unichar|AB3E|LATIN SMALL LETTER BLACKLETTER O WITH STROKE}} ** {{Unichar|AB3F|LATIN SMALL LETTER OPEN O WITH STROKE}} ** {{Unichar|AB43|LATIN SMALL LETTER TURNED O OPEN-O}} ** {{Unichar|AB44|LATIN SMALL LETTER TURNED O OPEN-O WITH STROKE}} * <sub>o</sub> : Subscript small o is used in [[Indo-European studies]]<ref>{{cite web|url=https://www.unicode.org/L2/L2004/04191-n2788-laryngeals.pdf|title=L2/04-191: Proposal to encode six Indo-Europeanist phonetic characters in the UCS|date=2004-06-07|first1=Deborah|last1=Anderson|first2=Michael|last2=Everson}}</ref> * 𝼛 : Latin small letter o with retroflex hook is used in [[phonetic transcription]]<ref name="L220125">{{Cite web|title=L2/20-125R: Unicode request for expected IPA retroflex letters and similar letters with hooks|url=https://www.unicode.org/L2/L2020/20125r-ipa-retroflex.pdf|date=2020-07-11|first=Kirk|last=Miller}}</ref><ref name="L221021">{{Cite web|title=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|url=https://www.unicode.org/L2/L2021/21021-consolidated-ipa.pdf|date=2020-12-07|first=Deborah|last=Anderson}}</ref> }}
===Derived signs, symbols and abbreviations=== * Ꝋ ꝋ : Forms of O were used for medieval [[scribal abbreviation]]s<ref name="unicode2006"/> * ∅ : [[Empty set|empty set symbol]]<ref>{{cite web|url=https://jeff560.tripod.com/set.html|title=Earliest Uses of Symbols of Set Theory and Logic|website=jeff560.tripod.com}}{{Dead link|date=May 2026 |bot=InternetArchiveBot }}</ref> * º : Masculine [[ordinal indicator]] * Calligraphic ''O'' (𝒪, 𝓸): [[Mathematical Alphanumeric Symbols]]<ref>{{Cite web |title=Script (or Calligraphic) |url=https://www.w3.org/TR/xml-entity-names/script.html |access-date=2024-01-03 |website=www.w3.org}}</ref>
===Ancestors and siblings in other alphabets=== * 𐤏 : [[Phoenician alphabet|Semitic]] letter [[Ayin]], from which the following symbols originally derive: ** Ω ω : [[Greek alphabet|Greek]] letter [[Omega]] ** Ο ο : Greek letter [[Omicron]] *** {{Script|Copt|Ⲟ ⲟ}} : [[Coptic alphabet|Coptic]] letter O, which derives from Greek omicron *** О о : [[Cyrillic]] letter [[O (Cyrillic)|O]], which also derives from Omicron *** 𐌏 : [[Old Italic script|Old Italic]] O, which derives from Greek Omicron, and is the ancestor of modern Latin O *** Օ օ : [[Armenian alphabet|Armenian letter O]]{{citation needed|date=October 2015}}
{{anchor|Codes for computing}}
==Other representations== ===Computing <span class="anchor" id="Computing codes"></span>===
* {{unichar| 004F }}
* {{unichar| 006F}} * {{unichar| FF2F | nlink= Half-width and full-width forms}} * {{unichar| FF4F }}
===Other=== {{Letter other reps |NATO=Oscar |Morse=––– |Character=O |Braille=⠕ |fingerspelling=O }} {{clear}}
==See also== * [[O mark]] * [[Open O]] (Ɔ ɔ) * [[0]] (zero). The capital letter O may be mistaken or misused for the number 0, as they appear quite identical in some typefaces. Early typewriters did not have a 'zero' key.
==Notes== {{Notelist}}
==References== {{Reflist}}
==External links== {{Wiktionary|O|o}} * {{Commons category-inline|O}}
{{Latin alphabet|O|}}
[[Category:ISO basic Latin letters]] [[Category:Vowel letters]]