watershed

American  

[waw-ter-shed, wot-er-] / ˈwɔ tərˌʃɛd, ˈwɒt ər- /

noun

• watersheds
  plural

1. Chiefly British. the ridge or crest line dividing two drainage areas; water parting; divide.

2. the region or area drained by a river, stream, etc.; drainage area.

3. Architecture. wash.

4. an important point of division or transition between two phases, conditions, etc..

   The treaty to ban war in space may prove to be one of history's great watersheds.

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adjective

1. constituting a watershed.

   a watershed area; a watershed case.

watershed British  

/ ˈwɔːtəˌʃɛd /

noun

1. the dividing line between two adjacent river systems, such as a ridge

2. an important period or factor that serves as a dividing line

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watershed Scientific  

/ wô′tər-shĕd′ /

1. A continuous ridge of high ground forming a divide between two different drainage basins or river systems.

2. The region enclosed by such a divide and draining into a river, river system, or other body of water.

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watershed Cultural  

1. 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.

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Discover More

By extension, a “watershed” is a critical point that serves as a dividing line: “The parties reached a watershed in the contract negotiations.”

Other Word Forms

Noun Inflected Forms

• watersheds
  plural

Etymology

Origin of watershed

First recorded in 1795–1805; water + shed ²

Explanation

A watershed is a turning point, or historic moment. The day you got your braces off might have been a watershed moment in your life. Watershed is a geographical term, originally. The area that drains into a single river is the watershed for that river. Watershed can also mean a ridge, like that formed by a chain of mountains, which sends water to two different rivers on either side. It's from this meaning that watershed came to mean a turning point or dividing line in social life.

Example Sentences

See Examples For:

watershed watersheds

For a short time in the summer of 2023, it seemed as if Haim's under-20 side might offer a watershed moment of unity and co-existence.

From BBC ● Sep. 17, 2026

Dennis Radtke, chairman of the CDU's employee wing, called Sunday's vote a "watershed moment" and said that "the usual platitudes about a 'bitter evening' and the need for analysis won't cut it".

From Barron's ● Sep. 7, 2026

“I think this could be a watershed moment for Europe,” Orsina said of the upcoming election.

From Los Angeles Times ● Sep. 5, 2026

Sheinbaum reached a watershed moment in her presidency last weekend when she forced Sinaloa state Gov. Rubén Rocha—a close ally of López Obrador—out of office.

From The Wall Street Journal ● Aug. 28, 2026

In 1954, as we have seen, the watershed of this branch of the Miramichi was heavily sprayed.

From "Silent Spring" by Rachel Carson

Addressing common criticisms, he pledged to keep electricity prices low by building its own energy-generating infrastructure wherever Meta invests and to restore more water than it uses in the watersheds it operates by 2030.

From MarketWatch ● Aug. 10, 2026

When exploring the watersheds east of Cuzco, Peru, he writes, Miller was “overawed by the tropical forest canopy stretching to infinity before him.”

From The Wall Street Journal ● Apr. 17, 2026

Large watersheds are far more common on Earth than on Mars.

From Science Daily ● Dec. 31, 2025

“Building the snowpack on hydrated watersheds will help us avoid losing potential spring runoff to dry soils later in the season,” Anderson wrote in an email.

From Los Angeles Times ● Nov. 24, 2025

Such places, the watersheds of the great coniferous forests of spruce and balsam, of hemlock and pine, provide the kind of spawning grounds that salmon must have in order to survive.

From "Silent Spring" by Rachel Carson

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