This is a good point: "middle voice" is potentially ambiguous because
it could refer to form (verbs with the reflexive suffix) or function
(verbs where the agent is also the recipient), this function being
just one among several uses of verbs with this suffix. By the same
reasoning "passive" would be equally ambiguous if we were to use that
for the form itself, as well as one of its functions.

> I recommend those not wanting to sound like newbie to avoid using the
> term "Middle Voice" to substitute the Icelandic spelling
> "MiðMynd".
> Use instead separately depending of the case terms
> like "reflexive" and "passive".

It may not be ideal, but the term "middle voice" has traditionally
been used for this verb form, e.g. in one of the standard textbooks,
Gordon's Introduction to Old Norse. Stefán Einarsson (1945) uses
"middle voice" for 'miðmynd' (Icelandic Grammar). Rory McTurk (2004)
uses "middle voice", "middle voice endings", "middle voice forms", in
The Icelandic Language, his translation of Stefán Karlsson's Tungan
(first published 1989). "Medio-passive" is used in Old Norse Online.
Zoega uses "reflexive". Jan Terje Faarlund calls it "the reflexive
verb form" in Old Norse Syntax (2004), but also tentatively uses the
term "medio-passive" to refer in a general way to its range of
functions. So you won't seem like a "newbie" when the experts can't
decide what's best to call it!

I am tempted to start calling it the "reflexive form" of the verb,
although one possible disadvantage with that is that a verb can also
be made reflexive with a freestanding reflexive pronoun.

Luckily, a lot of the time, there will be no ambiguity whichever term
is used, since it will be clear from the context whether the author is
writing about the verb-form or how it's used. Where not, you can
specify, e.g. "middle voice FORM". But I agree, it would be clearer
and more logical to have distinct terms for the form and its various
functions:

active "I dress you"
passive "I am dressed by you"
middle "I dress (myself)"
reciprocal "we dress each other"