Etymology tree Proto-Indo-European *peh₂ḱ- Proto-Indo-European *-s Proto-Indo-European *péh₂ḱs Proto-Italic *pāks Latin pāx Proto-Indo-European *dʰeh₁-der. Proto-Italic *-fakāō Latin -ficō Latin pacificō Proto-Indo-European *-tis Proto-Indo-European *-Hō Proto-Indo-European *-tiHō Proto-Italic *-tiō Latin -tiō Latin pācīfīcātīolbor. Polish pacyfikacja Learned borrowing from Latin pācīfīcātīo.