Definition Courtesy of Merriam-Webster
(Read it because you apparently failed grammar class.)
Pronunciation:
ˈyü, yə also yē\
Function:
pronoun
Etymology:
Middle English, from Old English ēow, dative & accusative of gē you; akin to Old High German iu, dative of ir you, Sanskrit yūyam you
Date:
Before 12th century.
The one or ones being addressed —used as the pronoun of the second person singular or plural in any grammatical relation except that of a possessive
<you may sit in that chair> < you are my friends><can I pour you a cup of tea> — used formerly only as a plural pronoun of the second person in the dative or accusative case as direct or indirect object of a verb or as object of a preposition — compare thee, thou, ye, your, yours.