From Proto-Germanic*arsaz, from Proto-Indo-European*h₃érsos, *ors-. Cognate with Old Frisian ers (West Frisian ears), Old Saxon ars, Old High German ars (German Arsch), Old Norse ars, rass (Icelandic and Norwegian rass), and more distantly with Old Armenian ոռ(oṙ, “ass”), and (Modern) Greek ουρά(ourá, “tail”).