Where does “Moesian” come from?

Moesian (English) comes from English ān, from Middle English ān, from Old English ān, from Proto-West Germanic ain, from Proto-Germanic ainaz, from Proto-Indo-European óynos — one; single.

Moesian (English): Of or relating to Moesia; A native or inhabitant...

Definitions

Of or relating to Moesia; A native or inhabitant...

Ancestry of “Moesian”, step by step

Moesian traces back through two separate lines of ancestry.

via English ān

Step	Language	Word	Meaning
1	English	ān	—
2	Middle English	ān	a, an indefinite article
3	Old English	ān	lonely; entirely alone, solitary, single; one
4	Proto-West Germanic	ain	one
5	Proto-Germanic	ainaz	one; some
6	Proto-Indo-European	óynos	one; single

via English Moesia

Step	Language	Word	Meaning
1	English	Moesia	—
2	Latin	Moesia	—
3	Ancient Greek	Μοισία	Moesia
4	Ancient Greek	-ῐ́ᾱ	{{l\|en\|-ia}}; "suffix forming abstract feminine...
5	Proto-Indo-European	-íh₂	—
6	Proto-Indo-European	-h₂	Creates collective nouns, which refer to groups...

Every word from Proto-Indo-European óynos →