Germanic cognates: Old Frisian thuner, Old Saxon thunar (Low German Donner), Dutch donder, Old High German Donar (German Donner), Old Norse Þórr (Swedish Tor).
Indo-European root cognates: Sanskrit स्तन्(stan), Ancient Greek στένει(sténei), Latin tonō, Old Church Slavonic стенати(stenati) (Russian стенать(stenatʹ)), Lithuanian steneti.