Thread:User talk:Rua/Proto-Balto-Slavic

Rua: An o-stem noun back-formed from *mēnsā́ˀ, the plural of Proto-Balto-Slavic *mḗns, from Proto-Indo-European *mḗms.

That's not so.

You have the wrong Proto-Balto-Slavic form. The original form was in the neuter gender. Next, there was a replacement of "-oN" with a pronominal-adjectival "-od". The neuter gender was preserved.