The close back unrounded vowel, or high back unrounded vowel, is a type of vowel

Vowel

In phonetics, a vowel is a sound in spoken language, such as English ah! or oh! , pronounced with an open vocal tract so that there is no build-up of air pressure at any point above the glottis. This contrasts with consonants, such as English sh! , where there is a constriction or closure at some...

 sound used in some spoken language

Language

Language may refer either to the specifically human capacity for acquiring and using complex systems of communication, or to a specific instance of such a system of complex communication...

s. The symbol in the International Phonetic Alphabet

International Phonetic Alphabet

The International Phonetic Alphabet "The acronym 'IPA' strictly refers [...] to the 'International Phonetic Association'. But it is now such a common practice to use the acronym also to refer to the alphabet itself that resistance seems pedantic...

 that represents this sound is ɯ. Typographically a turned letter m, given its relation to the sound represented by the letter u it can be considered a u with an extra "bowl". The sound is sometimes referred to as "unrounded u".

The IPA prefers terms "close" and "open" for vowels, and the name of the article follows this. However, a large number of linguists, perhaps a majority, prefer the terms "high" and "low", and these are the only terms found in introductory textbooks on phonetics

Phonetics

Phonetics is a branch of linguistics that comprises the study of the sounds of human speech, or—in the case of sign languages—the equivalent aspects of sign. It is concerned with the physical properties of speech sounds or signs : their physiological production, acoustic properties, auditory...

 such as those by Peter Ladefoged

Peter Ladefoged

Peter Nielsen Ladefoged was an English-American linguist and phonetician who traveled the world to document the distinct sounds of endangered languages and pioneered ways to collect and study data . He was active at the universities of Edinburgh, Scotland and Ibadan, Nigeria 1953–61...

.

Occurrence

Language		Word	IPA International Phonetic Alphabet The International Phonetic Alphabet "The acronym 'IPA' strictly refers [...] to the 'International Phonetic Association'. But it is now such a common practice to use the acronym also to refer to the alphabet itself that resistance seems pedantic...	Meaning	Notes
Alekano			[hɑnɯβɑ]	'nothing'
Azeri Azerbaijani language Azerbaijani or Azeri or Torki is a language belonging to the Turkic language family, spoken in southwestern Asia by the Azerbaijani people, primarily in Azerbaijan and northwestern Iran...			[ɡɯrx]	'forty'
Bashkir Bashkir language The Bashkir language is a Turkic language, and is the language of the Bashkirs. It is co-official with Russian in the Republic of Bashkortostan.-Speakers:...			[qɯð]	'girl'
Chinese Chinese language The Chinese language is a language or language family consisting of varieties which are mutually intelligible to varying degrees. Originally the indigenous languages spoken by the Han Chinese in China, it forms one of the branches of Sino-Tibetan family of languages...	Wu	父	[vɯ]	'father'
	Min Nan	豬	[tɯ]	'pig'
Crimean Tatar Crimean Tatar language The Crimean Tatar language is the language of the Crimean Tatars. It is a Turkic language spoken in Crimea, Central Asia , and the Crimean Tatar diasporas in Turkey, Romania, Bulgaria...			[dʒanɯm]	'please'
Irish Irish language Irish , also known as Irish Gaelic, is a Goidelic language of the Indo-European language family, originating in Ireland and historically spoken by the Irish people. Irish is now spoken as a first language by a minority of Irish people, as well as being a second language of a larger proportion of...	Ulster Ulster Irish Ulster Irish is the dialect of the Irish language spoken in the Province of Ulster. The largest Gaeltacht region today is in County Donegal, so that the term Donegal Irish is often used synonymously. Nevertheless, records of the language as it was spoken in other counties do exist, and help provide...		[kʰɯːl̪ˠ]	'narrow'	See Irish phonology Irish phonology The phonology of the Irish language varies from dialect to dialect; there is no standard pronunciation of the language. Therefore, this article focuses on phenomena that pertain generally to most or all dialects, and on the major differences among the dialects...
Korean Korean language Korean is the official language of the country Korea, in both South and North. It is also one of the two official languages in the Yanbian Korean Autonomous Prefecture in People's Republic of China. There are about 78 million Korean speakers worldwide. In the 15th century, a national writing...		/	[kɯm]	'gold'	See Korean phonology Korean phonology This article is a technical description of the phonetics and phonology of Korean.Korean has many allophones, so it is important here to distinguish morphophonemics from corresponding phonemes and allophones .-Consonants:The following are phonemic transcriptions of Korean consonants.# are voiced ...
Kyrgyz Kyrgyz language Kyrgyz or Kirgiz, also Kirghiz, Kyrghiz, Qyrghiz is a Turkic language and, together with Russian, an official language of Kyrgyzstan...			[qɯz]	'girl'
Ongota Ongota language Ongota is a moribund language of southwest Ethiopia. In 2008, it was said to be in a state of decline with only 6 elderly native speakers, the rest of their small village on the west bank of the Weito River having adopted the Tsamai language instead. The grammar follows a Subject Object Verb word...		[kuˈbuːɯ]		'dry'
Portuguese Portuguese language Portuguese is a Romance language that arose in the medieval Kingdom of Galicia, nowadays Galicia and Northern Portugal. The southern part of the Kingdom of Galicia became independent as the County of Portugal in 1095...	European		[pɯ̟ˈɣaɾ]	'to take'	Occurs in unstressed syllables. More commonly transcribed as /ɨ/. See Portuguese phonology Portuguese phonology The phonology of Portuguese can vary considerably between dialects, in extreme cases leading to difficulties in intelligibility. This article focuses on the pronunciations that are generally regarded as standard...
Sakha Sakha language Sakha, or Yakut, is a Turkic language with around 360,000 native speakers spoken in the Sakha Republic in the Russian Federation by the Sakha or Yakuts.Sakha is an agglutinative language, and it employs vowel harmony.-Classification:...			[tɯl]	'tongue'
Scottish Gaelic			[kʰɯːl̪ˠ]	'thin'	See Scottish Gaelic phonology Scottish Gaelic phonology This article is about the phonology of the Scottish Gaelic language. There is no standard variety of Scottish Gaelic; although statements below are about all or most dialects, the north-western dialects are discussed more than others as they represent the majority of speakers.Gaelic phonology is...
Sundanese Sundanese language Sundanese is the language of about 27 million people from the western third of Java or about 15% of the Indonesian population....			[mɯnaŋ]	'get'
Thai Thai language Thai , also known as Central Thai and Siamese, is the national and official language of Thailand and the native language of the Thai people, Thailand's dominant ethnic group. Thai is a member of the Tai group of the Tai–Kadai language family. Historical linguists have been unable to definitively...			[kʰɯn˥˩]	'to go up'
Turkish Turkish language Turkish is a language spoken as a native language by over 83 million people worldwide, making it the most commonly spoken of the Turkic languages. Its speakers are located predominantly in Turkey and Northern Cyprus with smaller groups in Iraq, Greece, Bulgaria, the Republic of Macedonia, Kosovo,...			[ɯˈɫɯk]	'warm'	See Turkish phonology Turkish phonology The phonology of the Turkish language describes the set of sounds and their relationships with one another in spoken Turkish. One characteristic feature of Turkish is a system of vowel harmony that distinguishes between front and back vowels. The majority of words in Turkish adhere to a system of...
Vietnamese Vietnamese language Vietnamese is the national and official language of Vietnam. It is the mother tongue of 86% of Vietnam's population, and of about three million overseas Vietnamese. It is also spoken as a second language by many ethnic minorities of Vietnam...			[tɯ]	'fourth'	See Vietnamese phonology Vietnamese phonology This article is a technical description of the sound system of the Vietnamese language, including phonetics and phonology.-Consonants:Two main varieties of Vietnamese, Hanoi and Ho Chi Minh City, are described below.-Hanoi:...

The symbol ⟨ɯ⟩ is sometimes used for Japanese

Japanese language

is a language spoken by over 130 million people in Japan and in Japanese emigrant communities. It is a member of the Japonic language family, which has a number of proposed relationships with other languages, none of which has gained wide acceptance among historical linguists .Japanese is an...

 /u/, but that sound is rounded, albeit with labial compression

Roundedness

In phonetics, vowel roundedness refers to the amount of rounding in the lips during the articulation of a vowel. That is, it is vocalic labialization. When pronouncing a rounded vowel, the lips form a circular opening, while unrounded vowels are pronounced with the lips relaxed...

 rather than protrusion. It is more accurately described as an exolabial close back vowel.