From Proto-Iranian *abráh, from Proto-Indo-Iranian *abʰrás, from Proto-Indo-European *n̥bʰrós (“rain-cloud, rain, cloud”). Cognates include Sanskrit अभ्र (abhrá), Old Armenian ամբ (amb), Latin imber and possibly Ancient Greek ἀφρός (aphrós) and ὄμβρος (ómbros).