If we must use "relative" then it would be better to say exactly
what we mean "relative to the wing/aircraft" or "in relation to
the wing/aircraft", but as this is the only relation that makes
sense when discussing AOA it shouldn't be necessary to mention
it at all.

That's why it's almost impossible to discuss a subject meaningfully
with someone unless he has the basic vocabulary down. For the CFIs I
have taught, my first step is have them read an entry-level
aerodynamics book. Much of our discussions after that is making sure
they use the correct words and have a clear idea of what they mean.

Words like "pitch", "angle of attack", and "climb angle" all have
different meanings, but the distinction is so fuzzy in most pilots'
minds that it's no wonder that people get confused.

Now, "relative wind" is a standard aerodynamics term and is as
ordinary to me as the word "chair". Surely all pilots understand what
relative wind is?


Yes, "wind" probably isn't the ideal word to use; vast numbers of
pilots out there still think that the motion of the airmass relative
to the ground affects the aerodynamics of the aircraft, and it's very
difficult to rid them of that notion.