Etymology tree Proto-Indo-European *per-der.? Proto-Indo-European *-tósder.? Proto-Slavic *portiti Proto-Indo-European *-yeh₂ Proto-Balto-Slavic *-jāˀ Proto-Slavic *-ja Proto-Slavic *porťa Old Czech prácěbor. Old Polish praca Polish praca Polish -uś Polish pracuś From praca + -uś.