This is the an area drained by a river, stream, or other water source.

Example: This can also be called a drainage basin.

Watershed

Explanation:

A watershed is an area drained by a river, stream or other water sources.

Most water shed are usually separated from one another by a continental divide. Such divides are extensive mountain ranges from which the rivers/streams takes their source. They flow into their drainage basin usually the ocean most times. Most watersheds are usually regions of good and fertile lands. Watershed drains all the rivers and streams in an area.