Definitions by Bean-chan
-chan
Japanese term of endearment. Normally used for a female, exceptions are often made for young children. Usually used with a first name. Sometimes used between people who are dating.
-san
Japanese equivalent of Mr/Mrs/Ms. Most often used with a person's surname, less commonly used with a person's given name. This is used for someone you do not know very well, like a classmate who isn't your friend and isn't in a higher grade, or a co-worker who isn't higher status than you.
-sama
A higher level of respect than -san. Can be used with a surname or given name, although being used with a surname is more common. Can be used for someone you greatly admire, but professionals of most areas are referred to as -sensei, or simply sensei.
-sensei
Used with masters of any profession. Teachers, scholars, etc. Can be added to the end of a name (usually the surname), or simply 'sensei' in replacement of any name at all. Not to be confused with someone who is of higher status than you in the school or workplace (-sempai).