It is defined as an elongate depression of the earth's surface usually between mountain or hill ranges. It is an area drained by a river and its tributaries. What is it commonly known as?

Valley is the correct answer. A valley is an elongated depression in the land surface, typically situated between mountain ranges or hills. Valleys are drained by rivers and their tributaries, which shape them over geological time. A canyon is a deep gorge with steep sides, a plain is flat land, and a plateau is elevated flat land. The question accurately describes a valley.