Belyak (unit)

Belyak was a fief or administrative subdivision in Medieval Volga Finnic states.

Etymology
The same as beylik, equivalent of county in other parts of Europe.

Medieval Volga Finnic States
Temnikov Principality and Mordvin Horde were divided into belyaks. After Russian Colonization they transformed into uyezds, modern day raions and aimaks in Mordovia.