I think most Muslim countries take their word for Greece from Arabic - Latin for Muslim nations, so we need to find out its origin in Arabic, IMHO.
The "Yunan" apparently comes from "Ionian".
More names for Greece in other languages."Yunan" comes from Ionia (the predominant Greek area of ancient Asia Minor) and it's used in Arabic and Farsi as well
Flaminius, see my post #2 Ionian Sea and islands is the name in English although in Greek it is Ionoi= Ιόνιοι.I am wondering where the "aan" part of Yuunaan comes from. Major pre-existing cognates do not seem to carry this extra portion. E.g., Yavan (Hebrew), Yavana (Sanskrit), Yona (Pali).
I wonder if you mean to say that the English "Ionian" and the Arabic "al-yuunaan" share the same origin after "-an" being a typical Latin suffix that makes adjectives for place names. I don't think Latin is more likely to be the source of the Arabic word than such Oriental languages as I mentioned in my previous post.Flaminius, see my post #2 Ionian Sea and islands is the name in English although in Greek it is Ionoi= Ιόνιοι.
Which is part of Greece the whole country is Hellas Ελλάς.