Where does “Douro” come from?
Douro (English) comes from Portuguese Douro, from Old Portuguese Doiro, from Latin Durius, from Proto-Celtic dubros, from Proto-Indo-European dʰubʰrós, from Proto-Indo-European dʰewbʰ-, from Proto-Indo-European dʰewh₂- — smoke; mist, haze.
Ancestry of “Douro”, step by step