watershed wa·ter·shed (wô'tər-shěd')
A ridge between two areas that directs drainage to either side.
The area of marginal blood flow at the extreme periphery of a vascular bed.
|watershed (wô'tər-shěd') Pronunciation Key
A ridge of high land dividing two areas that are drained by different river systems. On one side of a watershed, rivers and streams flow in one direction; on the other side they flow in another direction. Also, the area drained by a water system.
Note: By extension, a “watershed” is a critical point that serves as a dividing line: “The parties reached a watershed in the contract negotiations.”
area from which all precipitation flows to a single stream or set of streams. For example, the total area drained by the Mississippi River constitutes its drainage basin, whereas that part of the Mississippi River drained by the Ohio River is the Ohio's drainage basin. The boundary between drainage basins is a drainage divide: all the precipitation on opposite sides of a drainage divide will flow into different drainage basins.
Learn more about watershed with a free trial on Britannica.com.