byn - (aph.) to cause to understand
(DNWSI 152, Hillers; Cussini 346)
Note the semantic shift “to cause to understand” > “to lay down rules”
PWS
*byn - to (be) separate(d)
(DRS 62; Kogan 2015: 80)
the priority of the verbal root over the nominal formation *bayn- (Lipiński 1997:468) rather than vice versa remains to be substantiated (cf. Blažek 2007:32)