Süvendid

Süvendid are the plural of the Estonian noun süvend, meaning a natural hollow, depression, or basin in the landscape, or the bed of a body of water. The term is used in geography and geology to describe low-lying areas that may collect water or sediments. Natural süvendid are formed by tectonic subsidence, glacial erosion, river incision, or karst processes, and they can vary greatly in size from a few meters to several kilometers across. They may host lakes, wetlands, peatlands, or be filled with sediments. Some süvendid act as catchment areas, influencing local hydrology and microclimates.

In human contexts, süvendid can be modified or created for purposes such as water storage, agriculture, or mining (e.g., open pits that later become ponds). In topographic mapping, süvendid are identified by their low elevation relative to the surrounding terrain, and by their basin-like shapes. Süvendid are often included in geographic descriptions of regions, where they contribute to the landscape's relief and hydrology. The word also appears in dictionaries as a general term for any hollow or depression in the surface of the Earth or in water bodies, not restricted to a single type.