Meaning of U in English

I. U 1 BrE AmE , u /juː/ ( plural U’s, u’s ) noun

1 . [uncountable and countable] the 21st letter of the English alphabet

2 . [singular, uncountable] British English used to describe a film that has been officially approved as suitable for people of any age ⇨ PG SYN G American English

3 . [countable] British English a mark given to a student’s work to show that it is extremely bad

⇨ ↑ U-boat , ↑ U-turn

II. U 2 BrE AmE pronoun written informal

a way of writing ‘you’, used especially in emails and ↑ text message s :

I love U!

Longman Dictionary of Contemporary English.      Longman - Словарь современного английского языка.