The term "Cul-de-Sac Plain" refers to a specific geological feature characterized by a flat area surrounded by higher terrain, often resembling a dead-end street. This type of landform is typically found in regions where erosion has created a depression, allowing for the accumulation of sediment and vegetation. Cul-de-sac plains can be important for local ecosystems, providing habitats for various species. They may also serve as natural drainage areas, collecting water runoff from surrounding hills. Such plains are often studied in the context of geology and environmental science to understand their formation and ecological significance.