出典:Wiktionary
Presumably from an Doric (かつ also Boeotian) accusative which ends in -ών (-ṓn), or representing the archaic pronunciation, /diː.do᷇ːn/, of the Ancient Greek Δῑδοῦν (Dīdoûn); compare the regularly Romanised Dīdūn, which represents the Ancient Greek etymon’s first-century-BC Koine pronunciation, /diˈdun/.