A large area of flat or gently rolling land is called a plain.

Here are some other terms that can describe similar landforms:

* Prairie: A large, flat grassland, often with a temperate climate.

* Steppe: A large, dry grassland, typically found in semi-arid climates.

* Savanna: A grassland with scattered trees, found in tropical climates.

* Plateau: A large, flat area of land elevated above the surrounding area.

* Tableland: A flat-topped plateau.