A small, shallow body of standing freshwater is called a pond.
Ponds form when water collects in a natural or artificial depression. Rainfall, groundwater, runoff, glacial activity, floodplain cutoffs, and beaver dams can all create them. Most ponds are freshwater, although some may be brackish, and they are typically shallow enough for sunlight to reach much of the bottom.
There is no universally accepted boundary between a pond and a lake. Size, depth, vegetation, water temperature, and ecological function are often used together. One proposed guideline describes a pond as less than 5 hectares in area, less than 5 meters deep, and with less than 30 percent of its surface covered by emergent vegetation, but these are practical criteria rather than a global rule.
A pond is different from a river because it lacks continuous flowing water, and from a swamp because a swamp is a wetland dominated by trees or shrubs. Lakes are generally larger or deeper, though everyday usage varies.