U (У у; italics: У у) is a letter o the Cyrillic script. It commonly represents the close back roondit vowel/u/, somewhit like the pronunciation o ⟨oo⟩ in "boot". The forms o the Cyrillic letter U are similar tae the lawercase o the Latin letter Y (Y y; Y y), but, as wi maist Cyrillic letters, the upper an lawercase fairms are similar in shape differin mainly in size an vertical placement.
Historically, Cyrillic U evolved as a specifically East Slavic short fairm o the digraph ⟨оу⟩ uised in auncient Slavic texts tae represent /u/. The digraph wis itself a direct loan frae the Greek alphabet, whaur the combination ⟨ου⟩ (omicron-upsilon) wis an aa uised tae represent /u/.
↑However, many Dungan books are in fact set using Ӯ (with macron) instead of Ў with breve, e.g. the Dungan-Russian dictionary (1968). There is never an ambiguity, as this is the only У-with-a-diacritic in Dungan. It is used in Dungan syllables where pinyin would use -u, except in those with labial consonants (i.e. in du, ' nu, lu, gu, hu, zu, ru, etc., but not bu or mu)