A "cwm" is a geological term that refers to a bowl-shaped valley formed by glacial erosion. It is typically characterized by steep sides and a flat bottom, often containing a lake or a small stream. Cwms are commonly found in mountainous regions, particularly in areas like the Welsh mountains and the Scottish Highlands. The word "cwm" originates from the Welsh language, where it means "valley." These valleys are significant in understanding glacial processes and landscapes. Cwms can also provide unique ecosystems, supporting various plant and animal species adapted to the cooler, wetter conditions often found in these areas.