What is a "stub" nib, exactly?

[kcdan108]

OK, so obviously I'm new to this stuff, and if this has already been answered, please refer me to the correct thread.

I'm failing to understand what a stub or italic nib is exactly. I was under the impression that it was broader than a broad nib, but I've seen some people say things like, "ground to a fine stub nib. I only have a couple of fountain pens thus far, and I lean toward fine nibs (as I am an accountant), but understand that the real "art" of writing happens with broader nibs, and shading and such. Just need some definition/clarification. Thanks.