A drainage basin, also known as a watershed, is an area of land where all the water that falls as precipitation drains into a common outlet, such as a river, lake, or ocean. It includes all the streams, rivers, and lakes that collect and channel this water, as well as the surrounding land that contributes to the flow. The boundaries of a drainage basin are defined by high points, such as hills or mountains, which direct the flow of water. Understanding drainage basins is important for managing water resources, preventing flooding, and protecting ecosystems like wetlands and rivers.