While a waterfall is technically a feature of a watercourse rather than a standalone body of water like a lake or an ocean, it is part of a larger hydrological system. Geographically, a waterfall is defined as a point in a river or stream where water flows over a vertical drop or a series of steep drops. In common parlance, it is often grouped with "bodies of water" because it is a significant aquatic landmark. However, in scientific and legal terms, a body of water refers to a collection of water that is relatively still or has a distinct basin (like a pond, sea, or reservoir). A waterfall is a dynamic, moving flow of water, usually occurring in the upper course of a river. Despite this technicality, waterfalls are vital components of the freshwater ecosystem, providing aeration and unique habitats for specialized flora and fauna that thrive in the highly oxygenated "plunge pools" created at the base of the falls.