There is a legitimate confusion indeed and it seems to be on your part!

What I am talking about when I say "dynamic dispatch" is the sort of dispatching done by R, LISP and Julia (and not by C++ or Java). Now, we can bicker about labels and you can insist that it's actually called "multiple dispatch" and not "dynamic dispatch", but you can't bicker about the semantic fact that "multiple dispatch" is actually more dynamic than "dynamic dispatch".

And this semantic point would've been trivial to unpack if you weren't try to win an argument.

Indeed, sorry for engaging the trolls. 20; or 30 of you. Lost count.

So which textbook contains the meaning of "meaning"?

Oh, that's recursive! Which is Computer Science's domain of expertise, not the public domain.

We are talking about formal semantics here. What do programs (and computer languages are themselves programs) mean?

Point 0 of Wadler's law.

https://en.wikipedia.org/wiki/Semantics_(computer_science)

If you can type-check it at compile time then it is NOT dynamic dispatch. It's a contextual confusion.