Where does “Мејн” come from?

Мејн (Macedonian) comes from English maine, from French Maine, from Old French Cemaine, from Latin Cenomania.

Ancestry of “Мејн”, step by step

Step	Language	Word	Meaning
1	English	maine	Obsolete form of main
2	French	Maine	—
3	Old French	Cemaine	—
4	Latin	Cenomania	—