Real Dictionary

U
U or u is used as an abbreviation for words beginning with 'u', such as 'unit', 'united', or 'University'.
variable noun: U is the twenty-first letter of the English alphabet.

U in American English
noun: the 21st letter of the English alphabet, a vowel

U in American English 1
of the upper or wealthy class, esp. the British upper class, as characterized by supposedly definitive usages, accent, behavior, tastes, etc.
the twenty-first letter of the English alphabet: formerly a variant of V, v; not until the 18th cent. was it established as a vowel symbol only
pronoun: you

U in American English 2
atomic mass unit
uncle
adjective: characteristic of or appropriate to the upper class, esp. of Great Britain

U in American English 3
kosher (sense 1)
noun: a Burmese title of respect applicable to a man: used before the proper name

U in American English 4
uranium
symbol: certified as kosher by the Union of Orthodox Hebrew Congregations

u in British English
noun: the 21st letter and fifth vowel of the modern English alphabet

U in British English 1
abbreviation for: you
adjective: (esp of language habits) characteristic of or appropriate to the upper class
symbol for: united

U in British English 2
noun: (in Myanmar) a title of respect for men, equivalent to Mr

u. in American English
abbreviation: and
abbreviation: uncle

U. in British English
abbreviation for: union