Where does “*meinis” come from?

*meinis (Proto-Celtic) comes from Proto-Indo-European mēy(H)nis, from Proto-Indo-European (s)mēy(H)- — to cut, hew.

Ancestry of “*meinis”, step by step

Step	Language	Word	Meaning
1	Proto-Indo-European	mēy(H)nis	—
2	Proto-Indo-European	(s)mēy(H)-	to cut, hew

*meinis — Etymology, Origin & Word History | Etymology Explorer