Wadi (Arabic: وادي wādī; also: Vadi) is the Arabic term traditionally referring to a valley. In some cases, it may refer to a dry (ephemeral) riverbed that contains water only during times of heavy rain or simply an intermittent stream.
When Arab speakers live in a land with regular rivers—notably during Arab rule in the Iberian Al-Andalus—"wadi" might also be applied to these. For example, the name of the Spanish river Guadalquivir comes from the Arabical-wādi al-kabīr (الوادي الكبير), 'The Great River'.
Wadi Rum (Arabic: وادي رم) also known as The Valley of the Moon (Arabic: وادي القمر) is a valley cut into the sandstone and granite rock in southern Jordan 60 km (37 mi) to the east of Aqaba; it is the largest wadi in Jordan. The name Rum most likely comes from an Aramaic root meaning 'high' or 'elevated'. To reflect its proper Arabic pronunciation, archaeologists transcribe it as Wadi Ramm.