Where does “gemēne” come from?

gemēne (Old Frisian) comes from Proto-West Germanic gamainī, from Proto-Germanic gamainiz, from Proto-Indo-European ḱom-moynis.

Ancestry of “gemēne”, step by step

Step	Language	Word	Meaning
1	Proto-West Germanic	gamainī	common; shared, communal
2	Proto-Germanic	gamainiz	shared, communal, public; common, ordinary
3	Proto-Indo-European	ḱom-moynis	—

gemēne — Etymology, Origin & Word History | Etymology Explorer