Yu is a letter of the Cyrillic alphabet

Cyrillic alphabet

The Cyrillic script or azbuka is an alphabetic writing system developed in the First Bulgarian Empire during the 10th century AD at the Preslav Literary School...

. After a palatalized

Palatalization

In linguistics, palatalization , also palatization, may refer to two different processes by which a sound, usually a consonant, comes to be produced with the tongue in a position in the mouth near the palate....

 consonant, it represents the close back rounded vowel

Close back rounded vowel

The close back rounded vowel, or high back rounded vowel, is a type of vowel sound, used in many spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is , and the equivalent X-SAMPA symbol is u....

 /u/, somewhat like the pronunciation of ⟨oo⟩ in "boot"; elsewhere it is a so-called iotated

Iotation

Iotation is a linguistic phenomenon very characteristic of the Slavic languages. It should not be confused with palatalization, which is an entirely different process....

 vowel representing the combination /ju/, like the pronunciation of ⟨you⟩ in "youth". In English, Yu is commonly romanized

Romanization of Russian

Romanization of the Russian alphabet is the process of transliterating the Russian language from the Cyrillic alphabet into the Latin alphabet...

 as ⟨yu⟩.

History

Apart from the form I-O, in early Slavonic

Old Church Slavonic

Old Church Slavonic or Old Church Slavic was the first literary Slavic language, first developed by the 9th century Byzantine Greek missionaries Saints Cyril and Methodius who were credited with standardizing the language and using it for translating the Bible and other Ancient Greek...

 manuscripts the letter appears also in a mirrored form O-I . It is this form that is probably the original, precisely displaying the Greek combination omicron

Omicron

Omicron is the 15th letter of the Greek alphabet. In the system of Greek numerals it has a value of 70. It is rarely used in mathematics because it is indistinguishable from the Latin letter O and easily confused with the digit 0...

-iota

Iota

Iota is the ninth letter of the Greek alphabet. In the system of Greek numerals it has a value of 10. It was derived from the Phoenician letter Yodh . Letters that arose from this letter include the Roman I and J and the Cyrillic І , Yi , Je , and iotified letters .Iota represents...

 (οι). At the time that the Greek alphabet

Greek alphabet

The Greek alphabet is the script that has been used to write the Greek language since at least 730 BC . The alphabet in its classical and modern form consists of 24 letters ordered in sequence from alpha to omega...

 was adapted to the Slavonic language (giving rise to the Cyrillic alphabet), this denoted the close front rounded vowel

Close front rounded vowel

The close front rounded vowel, or high front 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 , and the equivalent X-SAMPA symbol is y...

 /y/ in educated Greek speech. This digraphic representation of /y/ was so basic for speakers of Greek that the simple letter upsilon

Upsilon

Upsilon is the 20th letter of the Greek alphabet.  In the system of Greek numerals it has a value of 400. It is derived from the Phoenician waw. The name of the letter is pronounced in Modern Greek, and in English , , or...

 (υ) representing the same sound came to be called υ ψιλόν (y psilon) "simple" υ in contrast to "complex" οι.

Probably in analogy to the 'iotated' letters , ІА, and , which fulfilled similar functions in Slavonic, this OI ligature was soon mirrored to the modern form ю.

Computing codes

character	Ю		ю
Unicode name	CYRILLIC CAPITAL LETTER YU		CYRILLIC SMALL LETTER YU
character encoding	decimal	hex	decimal	hex
Unicode Unicode Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...	1070	042E	1102	044E
UTF-8 UTF-8 UTF-8 is a multibyte character encoding for Unicode. Like UTF-16 and UTF-32, UTF-8 can represent every character in the Unicode character set. Unlike them, it is backward-compatible with ASCII and avoids the complications of endianness and byte order marks...	208 174	D0 AE	209 142	D1 8E
Numeric character reference Numeric character reference A numeric character reference is a common markup construct used in SGML and other SGML-related markup languages such as HTML and XML. It consists of a short sequence of characters that, in turn, represent a single character from the Universal Character Set of Unicode...	Ю	Ю	ю	ю
KOI8-R KOI8-R KOI8-R is an 8-bit character encoding, designed to cover Russian, which uses the Cyrillic alphabet. It also happens to cover Bulgarian, but is not used since CP1251 is accepted. A derivative encoding is KOI8-U, which adds Ukrainian characters...  and KOI8-U KOI8-U KOI8-U is an 8-bit character encoding, designed to cover Ukrainian, which uses the Cyrillic alphabet. It is based on KOI8-R, which covers Russian and Bulgarian, but replaces eight graphic characters with four Ukrainian letters Ґ, Є, І, and Ї in both upper case and lower case.In Microsoft Windows,...	224	E0	192	C0
CP 855 Code page 855 Code page 855 is a code page used under MS-DOS to write Cyrillic script. This code page is not used much.-Code page layout:...	157	9D	156	9C
Windows-1251 Windows-1251 Windows-1251 is a popular 8-bit character encoding, designed to cover languages that use the Cyrillic alphabet such as Russian, Bulgarian, Serbian Cyrillic and other languages...	222	DE	254	FE
ISO-8859-5	206	CE	238	EE
Mac Cyrillic MacCyrillic encoding The Macintosh Cyrillic encoding is used in Apple Macintosh computers to represent texts in the Cyrillic script.Each character is shown with its equivalent Unicode code point and its decimal code point. Only the second half of the table is shown, the first half being the same as ASCII....	158	9E	254	FE