What is you?
you is pron 1. referring to someone being spoken to Are you ready? You look tired, you should rest a bit. If I give you my address will you give me yours? Hello, how are you? Are you both keeping well? 2. referring to anyone You never know when you might need a penknife. You have to be very tall to be a policeman. 3. address- ing someone directly You with the red scarf over there, I need to see your ticket! Hey you! leave my bicycle alone. (NOTE: You is both singular and plural.)
source: Easier English, Student Dictionary Upper Intermediate Level