Etymology tree Proto-Indo-European *dʰeyh₂-der. Ancient Greek θεάομαι (theáomai) Proto-Indo-European *-tḗr Proto-Indo-European *-trom Proto-Hellenic *-tron Ancient Greek -τρον (-tron) Ancient Greek θέᾱτρον (théātron)der. Latin theātrumbor. French théâtrebor. Polish teatr Proto-Indo-European *h₂el-der.? Proto-Italic *-ālis Latin -alisbor. Proto-Indo-European *-nós Proto-Balto-Slavic *-inas…