Doab an area between two rivers, usually an upland or ridge between two adjacent valleys that contain streams flowing parallel approximately in the same direction. The Persian word 'do' means two and 'ab' means water; hence doab means two streams. In the Indo-Gangetic plain of northern India and Bangladesh, the term means low-lying, alluvial land between two confluent rivers. Specifically, it refers to the tract between the ganges and the jamuna. The term is commonly restricted to alluvial plains characterised by very little relief. An important example of doab in Bangladesh is Meghna-Shitalakshya doab. This large piece of land includes part of the Shitalakshya-Bangshi doab to the west. This doab is low and very fertile. Geographically, a doab is termed as interfluve. [Md Mahbub Murshed]