A watercourse is any natural or man-made channel where water flows, like a stream, river, canal, or even a drainage ditch. The word captures the idea of water following a course or path through the landscape.

Natural watercourses include babbling brooks in forests, mighty rivers like the Mississippi, and seasonal streams that only flow after heavy rains. Man-made watercourses include irrigation canals that farmers dig to bring water to their crops, aqueducts that ancient Romans built to supply cities with fresh water, and drainage channels that direct water away from roads and buildings.

The word emphasizes the pathway aspect: water doesn't just sit there, it travels along a defined route. When engineers plan a new development, they carefully map existing watercourses to avoid blocking natural drainage patterns. When hikers study topographic maps, they look for watercourses to find water sources or understand how the land slopes.

You might encounter this word in geography class when studying how rivers carve valleys, or in history when learning about civilizations that built elaborate watercourse systems. A dry watercourse, sometimes called a wash or arroyo in desert regions, shows where water flows during certain seasons, even though it's empty most of the year.