"telephoto" - another definition problem

I decided I might like a "true" very-high-quality 1:1 macro lens for
the EOS mount so I did a search on "process lens" (due to a discussion
in another thread that suggested a 1:1 top quality symettrical "macro"
lens is called a "process lens") and did not find any EOS Canon lenses
to match. That's not saying there is no such thing - but I didn't find
any. I am guessing they will be called "macro" lenses and I wonder if I
could tell if it were optimised for 1:1. But never mind, the word
"macro" means different things to different people and it seems like
the camera manufacturers prefer to keep people confused as to the
definition. But that aside, I walked two doors down the corridor to ask
a fellow photography enthusiast what his definition of "telephoto" was.
It was different to mine.

So what is the definition of "telephoto"?

And once we are all sure of what it is, then what is the definition of
"reverse telephoto" and "telephoto ratio" and does this fit with the
definition of "telephoto"?