"Õ" (uppercase), or "õ" (lowercase) is a composition of the

Latin letter The Latin script, also known as the Roman script, is a writing system based on the letters of the classical Latin alphabet, derived from a form of the Greek alphabet which was in use in the ancient Greek city of Cumae in Magna Graecia. The Gree ...

O with the

diacritic A diacritic (also diacritical mark, diacritical point, diacritical sign, or accent) is a glyph added to a letter or to a basic glyph. The term derives from the Ancient Greek (, "distinguishing"), from (, "to distinguish"). The word ''diacrit ...

mark

tilde The tilde (, also ) is a grapheme or with a number of uses. The name of the character came into English from Spanish , which in turn came from the Latin , meaning 'title' or 'superscription'. Its primary use is as a diacritic (accent) in ...

. The

HTML entity In SGML, HTML and XML documents, the logical constructs known as ''character data'' and ''attribute values'' consist of sequences of characters, in which each character can manifest directly (representing itself), or can be represented by a series ...

is ''Õ'' for Õ and ''õ'' for õ.

Romagnol

For Romagnol language, ''õ'' is used in some proposed orthographies to represent , e.g. ''savõ'' "soap". To this day a unified standardization has not been established.

Estonian

Estonian Estonian may refer to: * Something of, from, or related to Estonia, a country in the Baltic region in northern Europe * Estonians, people from Estonia, or of Estonian descent * Estonian language * Estonian cuisine * Estonian culture See also

...

, ''Õ'' is the 27th letter of the

alphabet An alphabet is a standard set of letter (alphabet), letters written to represent particular sounds in a spoken language. Specifically, letters largely correspond to phonemes as the smallest sound segments that can distinguish one word from a ...

(between W and Ä), and it represents a vowel characteristic of Estonian, the unrounded back vowel , which may be close-mid back, close back, or close-mid central. The vowel was previously written with the letter Ö, but in the early 19th century, Otto Wilhelm Masing adopted the letter ''Õ'', ending the confusion between several homographs and clearly showing how to pronounce a word. In informal writing, e.g., emails, instant messaging and when using foreign keyboard layouts where the letter ''Õ'' is not available, some Estonians use the characters O or 6 to approximate this letter. In most parts of the island

Saaremaa Saaremaa (; ) is the largest and most populous island in Estonia. Measuring , its population is 31,435 (as of January 2020). The main island of the West Estonian archipelago (Moonsund archipelago), it is located in the Baltic Sea, south of Hi ...

, ''Õ'' is pronounced the same as ''Ö''.

Guarani

In the

Guarani language Guarani (Avañe'ẽ), also called Paraguayan Guarani, is a language of South America that belongs to the Tupi–Guarani branch of the Tupian languages, Tupian language family. It is one of the two official languages of Paraguay (along with Spa ...

, ''Õ'' is the 22nd letter and fourth nasal vowel of the alphabet, similar to the

Spanish Spanish might refer to: * Items from or related to Spain: **Spaniards are a nation and ethnic group indigenous to Spain **Spanish language, spoken in Spain and many countries in the Americas **Spanish cuisine **Spanish history **Spanish culture ...

"o", but with a stressed nasalization.

Hungarian

In Hungarian, Õ only appears when a typeface (font set) does not contain a proper "ő" letter, which is an "o" with a double acute diacritic.

Samogitian

In Samogitian the letter ''Õ'' represents, as in Estonian, the unrounded back vowel which is unique to Samogitian and is not found in Standard Lithuanian, this is a rather new innovation brought on by the ensuing efforts of standardising Samogitian, this letter alleviates the confusion between the two distinct pronunciations of the letter ė.

Portuguese

In the

Portuguese language Portuguese ( or ) is a Western Romance language of the Indo-European language family originating from the Iberian Peninsula of Europe. It is the official language of Angola, Brazil, Cape Verde, Guinea-Bissau, Mozambique, Portugal and São Tom� ...

, the symbol ''Õ'' stands for a

nasal Nasal is an adjective referring to the nose, part of human or animal anatomy. It may also be shorthand for the following uses in combination: * With reference to the human nose: ** Nasal administration, a method of pharmaceutical drug delivery * ...

close-mid back rounded vowel The close-mid back rounded vowel, or high-mid back rounded vowel, is a type of vowel sound used in some spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is . Close-mid back protruded vowel The clo ...

, also written in IPA. It is not considered an independent letter of the

: the tilde is the standard diacritic for

nasalization In phonetics, nasalization (or nasalisation in British English) is the production of a sound while the velum is lowered, so that some air escapes through the nose during the production of the sound by the mouth. An archetypal nasal sound is . ...

Vietnamese

In the

Vietnamese language Vietnamese () is an Austroasiatic languages, Austroasiatic language Speech, spoken primarily in Vietnam where it is the official language. It belongs to the Vietic languages, Vietic subgroup of the Austroasiatic language family. Vietnamese is s ...

, the symbol ''Õ'' stands for the sound with

creaky voice In linguistics, creaky voice (sometimes called laryngealisation, pulse phonation, vocal fry, or glottal fry) refers to a low, scratchy sound that occupies the vocal range below the common vocal register. It is a special kind of phonation in which ...

(rising tone with a glottal break followed by a continuation of the rising tone). Vietnamese also has derived letters Ỗ/ỗ and Ỡ/ ỡ.

Võro

In the

Võro language Võro ( ; , ) is a South Estonian language. It has its own literary standard and efforts have been undertaken to seek official recognition as an indigenous regional language of Estonia. Võro has roughly 75,000 speakers (Võros), mos ...

, this letter is the 25th letter of the alphabet, pronounced as in Estonian.Omniglot
/ref>

Skolt Sami

In the Skolt Sami language, this letter is the 25th letter of the alphabet, pronounced as [].

Voko

In the Voko language, the letter ''Õ'' represents 'ɔ̀ŋ'.

Mathematical use

The symbol, pronounced Big oh notation#Extensions to the Bachmann–Landau notations, soft-''O'', is used as a variant of big O notation, big ''O'' notation to measure growth rate that ignores logarithmic factors. Thus,

f(n)\in\tilde(g(n))

shorthand Shorthand is an abbreviated symbolic writing method that increases speed and brevity of writing as compared to Cursive, longhand, a more common method of writing a language. The process of writing in shorthand is called stenography, from the Gr ...

for

\exists k:f(n) \in O(g(n) \log^kn)

Computer encoding

Due to

character encoding Character encoding is the process of assigning numbers to graphical character (computing), characters, especially the written characters of human language, allowing them to be stored, transmitted, and transformed using computers. The numerical v ...

confusion, the letters can be seen on many incorrectly coded Hungarian web pages, representing Ő/ő (letter O with

double acute accent The double acute accent () is a diacritic mark of the Latin and Cyrillic scripts. It is used primarily in Hungarian or Chuvash, and consequently it is sometimes referred to by typographers as hungarumlaut. The signs formed with a regular umlau ...

). This can happen due to said characters sharing a

code point A code point, codepoint or code position is a particular position in a Table (database), table, where the position has been assigned a meaning. The table may be one dimensional (a column), two dimensional (like cells in a spreadsheet), three dime ...

in the

ISO 8859-1 ISO/IEC 8859-1:1998, ''Information technology— 8-bit single-byte coded graphic character sets—Part 1: Latin alphabet No. 1'', is part of the ISO/IEC 8859 series of ASCII-based standard character encodings, first edition published in 19 ...

and 8859-2 character sets, as well as the

Windows-1252 Windows-1252 or CP-1252 ( Windows code page 1252) is a legacy single-byte character encoding that is used by default (as the "ANSI code page") in Microsoft Windows throughout the Americas, Western Europe, Oceania, and much of Africa. Initially ...

and

Windows-1250 Windows-1250 is a code page used under Microsoft Windows to represent texts in Central European and Eastern European languages that use the Latin script. It is primarily used by Czech. It is also used for Polish (as can Windows-1257), Slovak, H ...

character sets, and the web site designer forgetting to set the correct

code page In computing, a code page is a character encoding and as such it is a specific association of a set of printable character (computing), characters and control characters with unique numbers. Typically each number represents the binary value in a s ...

. Õ is not part of the Hungarian alphabet. The usage of

Unicode Unicode or ''The Unicode Standard'' or TUS is a character encoding standard maintained by the Unicode Consortium designed to support the use of text in all of the world's writing systems that can be digitized. Version 16.0 defines 154,998 Char ...

avoids this type of problems. In

LaTeX Latex is an emulsion (stable dispersion) of polymer microparticles in water. Latices are found in nature, but synthetic latices are common as well. In nature, latex is found as a wikt:milky, milky fluid, which is present in 10% of all floweri ...

the option of using "\~o" and "\~O" exists.

References

* {{DEFAULTSORT:O-Tilde Latin letters with diacritics Vowel letters