Maybe it's not the most useful concept (in my mindset) to bring across from C to perl with me...

Definitely, cause Perl's "&" never does anything similar to C's "&". Perl's "\" would be the closest to C's "&".

anyhow you can dereference a code reference in perl without the ampersand

$ref->(), although I don't see how the question relevant.

so any argument about what ampersand actually does in perl is debatable

Not really. It can be used to bypass prototypes (&func(...)), to call a func with parent's args (&func;), to dereference a code ref (&$ref) and surely more. None of them return an address (like C's "&") or anything similar (like Perl's "\").

dereferencing is literally accessing something at the address pointed by variable value

Not in any version of Perl. C pointers may be a fact of the implementation of Perl 5, but there is no language requirement for anything of the sort.

I don't understand your disagreement. The quoted statement seems obvious to me. If your language can dereference, you have references, and if you have references, you have some form of addressing. Dereferencing is the act of finding what's referenced (pointed to) by that reference (address).

I suppose the use of the word "addressing" sounds awfully much like raw pointers in C to me. I see what you mean; perhaps I'm drawing too fine a distinction.