What's the Difference Between a Nickname and a Name?

A lot of times people when they're talking to other people that they know they call them by a some kinship term or something. It's also very common for there to be combinations of things and even a teacher for example you would never call a teacher by their nickname but you would stick Mr. Teacher. There are all kinds of different things going on with formality that keep things not too informal if you know what I'm talking about A nickname does not automatically equal informality in in a specific way either not only so that's that's an interesting sort of thing it's definitely much more towards the cultural end but names are slightly connected with language so I wanted to cover that any other bits