Try to write an interpreter or compiler (for a language with functions of at least one argument). If you don't get the difference there, you will be in deep trouble.

Actually I'm working with Clang so that's when and why I wrote this article ;)

Good example. First I've seen, and it doesn't apply to me so I will continue using them as I have, but good example.

I bet you do know the difference - you just didn't know the words. And now you do!

I don't see how you could do any high-level programming without understanding the difference between defining a function and calling it.

I think you misunderstood collyw's original comment (or maybe I did?) - it's not pedantic to understand the conceptual difference, it's pedantic to worry about the terminology. (Except if you're writing a compiler, I guess, which most programmers are not.)

No, you misunderstand me (and the fault could be mine): my point is that since it's pedantic to worry about the terminology, you might as well use the standard terms. Leave it to others to waste their time worrying about what things are called.

pretty much