This is interesting, especially with you two Germans chiming in.

I've got a German colleague who got onto the topic of baking one time and said he wanted some bread. I directed him to the hospital cafeteria and he said that wasn't real bread. I didn't pursue.

I don't have any real understanding of bread and my own understanding is based on the Chinese character bao (包), and bread is just called 麵包 (wheat bao). To me, wheat + water + make it rise = some type of bread, but I get that this is a very basic understanding. Wiki link for chinese bao calls it a bun, which I also agree with.

What I don't quite get, is that the difference between bun and bread is apparently size and number of servings? So if I just made a basketball sized bun, that's now bread?

Pizza dough apparently has higher gluten than regular bread dough.

And when I was young, we had this thing at the supermarket called Pizza Bread, which was actually some toppings that you'd commonly find on pizzas placed on a bun.