Old Church Slavonic прагъ

← Proto-Balto-Slavic *porʔgos (derived)

← Proto-Indo-European *porg-o- (derived)

← Italian pergola (mention)

← Latin pergula (cognate)

← Proto-Slavic *porgъ (inherited)

→ Lower Sorbian prog (cognate)

→ Latin pergula (cognate)