Thai people have a first name, a surname, and a nickname, given at birth. They always call themselves by their nickname, and the first name is only used in official occasions (at school, or on any administrative document). Sometimes people are friends but they don't even know their real first or last name, because they only use their nicknames. Nicknames are usually short, and some of them have a meaning (which can be Small, Fish, Shrimp... anything, really!).