What does the term "wadi" mean in Arabic?

Wadi is an Arabic word often translated to valley. Officially wadi refers specifically to dry river beds and can also relate to smaller geographic formations. Wadi Rum is one of many well known locations that have given the word a cross lingual recognition.

Throughout the deserts of the Middle East there are few permanent water ways. The term Wadi relates specifically to these dry channels. As can be observed in Wadi Rum, the sandy sediments in the valleys are run off from the surrounding sandstone mountains. In times of heavy rain, strong water can wash through the valleys and shift large volumes of sand. This is the defining characteristic of the term ‘wadi’ in Arabic.