peneplain

A nearly flat land surface representing an advanced stage of erosion.

To reduce by erosion to a peneplain.

In geology, a surface reduced by erosion nearly to the condition of a plain. There are many examples of once lofty mountains, now reduced to peneplains.

A land surface reduced by erosion to the general condition of a plain, but not wholly devoid of hills; a base-level plain.

A low-relief plain representing the final stage of fluvial erosion during times of extended tectonic stability.

a more or less level land surface representing an advanced stage of erosion undisturbed by crustal movements