{{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=Latinlanguage |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=class=skin-invert-image|20px|Proto-sinaitic ʿayin |fam3=class=skin-invert-image|20px |fam4=class=skin-invert-image|20px|Phoenician Ayin |fam5=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|ע|ع|ܥ|ࠏ|ዐ|ࡘ|ჺ|Ո ո|Օ օ|ᱳ|ᱜ ᱣ}} |equivalents= |associates=o(x) |direction=Left-to-right |image=File:Latin_letter_O.svg |imageclass=skin-invert-image }} {{Latin letter info|o}}
'''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.<!--it's not necessarily the 4th vowel in Basic Latin, as <j> is sometimes used as a vowel.--> Its name in English is ''o'' (pronounced {{IPAc-en|'|oʊ|audio=LL-Q1860 (eng)-Flame, not lame-O.wav}}), plural ''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> <!--|class=skin-invert-image |class=skin-invert-image|65px |class=skin-invert-image|65px |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 syllables. 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 ! Phoenician<br/>Ayin ! Western Greek<br/>Omicron ! Etruscan<br>O ! Latin<br/>O |--- align=center |alt=Egyptian Hieroglyph describing an eye|45px |30px |30px |25px |x30px|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 {{IPAblink|ʕ}}, the sound represented by the cognate Arabic letter 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 alphabets, 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 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 ! Phonemes |- ! Catalan | {{IPAslink|ɔ}}, {{IPAslink|o}}, {{IPAslink|u}}, {{IPAslink|w}} |- ! {{nwr|Standard Chinese (Pinyin)}} | {{IPAslink|ə}}, {{IPAslink|u}} |- ! Czech | {{IPAslink|ɔ}} |- ! Danish | {{IPAslink|ɒ|ɔ}}, {{IPAslink|o}}, {{IPAslink|oː}} |- ! Dutch | {{IPAslink|ɔ}}, {{IPAslink|oː}}, {{IPAslink|ə}} |- ! English | {{IPAslink|ɒ}}, {{IPA|/oʊ/}}, {{IPAslink|ə}}, {{IPAslink|ɔː}}, {{IPA|/aɪə/}} |- ! French | {{IPAslink|o}}, {{IPAslink|ɔ}} |- ! German | {{IPAslink|ɔ}}, {{IPAslink|oː}}, {{IPAslink|o}} |- ! Irish | {{IPAslink|ɔ}}, {{IPAslink|ə}} |- ! Italian | {{IPAslink|o}}, {{IPAslink|ɔ}} |- ! Malagasy | {{IPAslink|u}} |- ! Malay | {{IPAslink|ɔ}} |- ! Norwegian | {{IPAslink|ɔ}}, {{IPAslink|ʊ}}, {{IPAslink|oː}}, {{IPAslink|uː}} |- ! Occitan | {{IPAslink|u}} |- ! Polish | {{IPAslink|ɔ}} |- ! Portuguese | {{IPAslink|ɔ}}, {{IPAslink|o}}, {{IPAslink|u}}, {{IPAslink|w}} |- ! Spanish | {{IPAslink|o}} |- ! Slovak | {{IPAslink|ɔ}} |- ! Swedish | {{IPAslink|ɔ}}, {{IPAslink|oː}}, {{IPAslink|uː}} |- ! Turkish | {{IPAslink|o}} |}
===English=== The letter {{angbr|o}} is the fourth 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 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, {{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 ''OE'' ligature * O with diacritics: Ø ø Ǿ ǿ Ö ö Ȫ ȫ Ó ó Ò ò Ô ô Ố ố Ồ ồ Ổ ổ Ỗ ỗ Ộ ộ Ǒ ǒ Ő ő Ŏ ŏ Ȏ ȏ Ȯ ȯ Ȱ ȱ Ọ ọ 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 Ớ ớ Ờ ờ Ỡ ỡ Ợ ợ Ở ở Ỏ ỏ Ō ō Ṓ ṓ Ṑ ṑ Õ õ Ȭ ȭ Ṍ ṍ Ṏ ṏ Ǫ ǫ Ȍ ȍ O̩ o̩ Ó̩ ó̩ Ò̩ ò̩ Ǭ ǭ O͍ o͍ * Ꝍ ꝍ : O with loop was used in some medieval Nordic 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> * IPA-specific symbols related to O: {{IPA link|ɔ}} * 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 abbreviations<ref name="unicode2006"/> * ∅ : 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 : Semitic letter Ayin, from which the following symbols originally derive: ** Ω ω : Greek letter Omega ** Ο ο : Greek letter Omicron *** {{Script|Copt|Ⲟ ⲟ}} : Coptic letter O, which derives from Greek omicron *** О о : Cyrillic letter O, which also derives from Omicron *** 𐌏 : Old Italic O, which derives from Greek Omicron, and is the ancestor of modern Latin O *** Օ օ : 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