Peneplain

In geomorphology and geology, a peneplain is a low relief plain formed by protracted erosion. In its broadest sense the term describes any such low relief erosional surface, though it is often used to imply the near final stage of fluvial erosion reached during a long period of tectonic stability. Peneplains are sometimes associated with William Morris Davis's cycle of erosion theory, though Davis and other researchers have also used the term in a purely descriptive sense with no theory or particular origin attached.