watershed

noun

wa·​ter·​shed ˈwȯ-tər-ˌshed 

ˈwä-

plural watersheds

1

a

: a dividing ridge between drainage areas : divide entry 2

The watershed of the Himalayas does not lie along the line of its highest peaks, as in most mountain ranges, but about a hundred miles farther north.

—Frits Staal

b

: a region or area bounded peripherally by a divide and draining ultimately to a particular watercourse or body of water

the Mississippi River watershed

2

: a crucial dividing point, line, or factor : turning point

This year marked a watershed for contemporary classical music in the city.

—The Chicago Tribune

The spring of 1949 was, in general, a watershed in Joe Liebling's life.

—Raymond Sokolov

The death of Ugandan teacher Gregory Byaruhanga at the hands of the Kenyan police has marked a watershed in the rising tension in the region and in the instability of the Kenyan regime.

—Victoria Brittain

—often used before another noun

a watershed moment

a watershed event

The watershed year for science fiction must be 1968, when Stanley Kubrick's 2001: A Space Odyssey appeared, not only dramatically expanding for this kind of motion picture the potentials of film technology, but making science fiction a vehicle for both poetic vision and metaphysical exploration.

—Ira Konigsberg

3

British : the time of day after which television programs not appropriate for children may be broadcast

the nine o'clock watershed

4

medical : an area of tissue (as of the brain or colon) that is located at the periphery of two separate arterial systems, is dependent on both for blood supply, and may be poorly perfused and vulnerable to ischemia

—usually used before another noun

Brain imaging of patients with vascular dementia typically show small strokes or poor blood supply deep in the brain, at the natural terminal (the so-called watershed area) of the blood vessel.

—Renee Meyer

… cell death caused by blocked blood flow in the brain's "watershed" region, where two arteries supply blood.

—Susan Scutti

see also watershed infarction

Did you know?

Watershed Has Geographic Origins

Opinion on the literal geographic meaning of watershed is divided. On one side of the debate are those who think the word can only refer to a ridge of land separating rivers and streams flowing in one direction from those flowing in the opposite direction. That's the term's original meaning, one probably borrowed in the translation of the German Wasserscheide. On the other side of the argument are those who think watershed can also apply to the area through which such divided water flows. The latter sense is now far more common in America, but most Americans have apparently decided to leave the quarrel to geologists and geographers while they use the term in its figurative sense, "turning point."        

Synonyms

• climacteric
• climax
• corner
• landmark
• milepost
• milestone
• turning point

Examples of watershed in a Sentence

The show will not air until after the nine o'clock watershed.

a watershed moment in her life came when she inherited a reasonable sum of money and was able to start her own coffee shop

Recent Examples on the Web

And that fear has started playing out in both watersheds as Indiana dialed back its protections in February for the state's most regulated wetlands, making the permitting process easier for developers to build on them. —Laura Schulte, Journal Sentinel, 3 Apr. 2024

In Namibia a team of National Geographic researchers has exposed test drilling within the watershed by a Canadian oil exploration company. —Alex Postman, Condé Nast Traveler, 1 Apr. 2024

That means the water that flows into the Wabash River from the west may soon be governed by very different standards than its watershed on the eastern side. —Tribune News Service, The Mercury News, 1 Apr. 2024

Invading junipers create wildfire risks that can damage infrastructure and communities and reduce the efficiency of runoff into the watershed. —Hayleigh Evans, The Arizona Republic, 28 Mar. 2024

Tap on watersheds, streams and reservoirs for more information on levels and flow rates. —David Montesino, Fort Worth Star-Telegram, 25 Mar. 2024

At the same time, the intake capacity of 6,000 cubic feet per second is a small fraction of what can move through the watershed. —Hayley Smith, Los Angeles Times, 29 Feb. 2024

Its Day-Date model unveiled a year ago, featuring a multicolored dial of enameled puzzle pieces, with emoji (a heart, a kissy face, etc.) and inspirational words replacing the days and dates, is too rare to be seen as a watershed but was a shock nonetheless. —Tim Barber, WIRED, 26 Mar. 2024

In follow-up emails and a phone call, spokespeople for the state said the fines cover the first phase of the Cymric spill, in which a river of thick crude flowed down a natural watershed. —Janet Wilson, ProPublica, 22 Mar. 2024

Word History

First Known Use

1764, in the meaning defined at sense 1a

Phrases Containing watershed

• watershed infarct
• watershed infarction
• watershed stroke

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Kids Definition

watershed

noun

wa·​ter·​shed ˈwȯt-ər-ˌshed 

ˈwät-

1

: a dividing ridge (as a mountain range) separating one drainage area from others

2

: the area that drains into a river or lake