U (Cyrillic)

U (У у; italics: У у ) is a letter of the Cyrillic script. It commonly represents the close back rounded vowel, somewhat like the pronunciation of $\langleoo\rangle$ in "boot" or "rule". The forms of the Cyrillic letter U are similar to the lowercase of the Latin letter Y (Y y; Y y ), with the lowercase Cyrillic letter U's form being identical to that of small Latin letter Y.

History
Historically, Cyrillic U evolved as a specifically East Slavic short form of the digraph $\langleоу\rangle$ used in ancient Slavic texts to represent. The digraph was itself a direct loan from the Greek alphabet, where the combination $\langleου\rangle$ (omicron-upsilon) was also used to represent. Later, the o was removed, leaving the modern upsilon-only form.

Consequently, the form of the letter is derived from Greek upsilon $\langleΥ υ\rangle$, which was parallelly also taken over into the Cyrillic alphabet in another form, as Izhitsa $\langleѴ\rangle$. (The letter Izhitsa was removed from the Russian alphabet in the orthography reform of 1917/19.)

It is normally romanised as "u", but in Kazakh, it is romanised as "w".

In the Cyrillic numeral system, the Cyrillic letter U had a value of 400.

In other languages
In Tuvan the Cyrillic letter can be written as a double vowel.

In certain languages, U is used to mark labialization.

Related letters and other similar characters

 * Υ υ : Υ|Greek letter Upsilon
 * U u : U|Latin letter U
 * Y y : Y|Latin letter Y
 * Ў ў : Ў|Cyrillic letter Short U, used in Belarusian, Dungan, Siberian Eskimo (Yuit), Uzbek
 * Ӯ ӯ : Ӯ|Cyrillic letter U with macron, used in Tajik and Carpatho-Rusyn
 * Ӱ ӱ : Ӱ|Cyrillic letter U with diaeresis, used in Altai (Oyrot), Khakas, Gagauz, Khanty, Mari
 * Ӳ ӳ : Ӳ|Cyrillic letter U with double acute, used in Chuvash
 * Ү ү : Ү|Cyrillic letter straight U, used in Mongolian, Kazakh, Tatar, Bashkir, Dungan and other languages
 * Ұ ұ : Ұ|Cyrillic letter Straight U with stroke, used in Kazakh
 * Ꭹ Ꮍ : The syllables gi and mu of the Cherokee syllabary; Ꭹ (gi) notably appearing in the Cherokee self-designation ᏣᎳᎩ (Tsalagi)
 * ע: The Hebrew letter Ayin
 * У̊: Cyrillic letter U with ring,used in shugnhi orthography.