wa·​ter·​shed ˈwȯ-tər-ˌshed How to pronounce watershed (audio)
plural watersheds
: 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
: a region or area bounded peripherally by a divide and draining ultimately to a particular watercourse or body of water
the Mississippi River watershed
: 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 momenta watershed eventThe 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
British : the time of day after which television programs not appropriate for children may be broadcast
the nine o'clock watershed
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."        

Example Sentences

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 Southward along the Mississippi, other areas of the watershed did not have record snow, so other tributaries along the river aren't contributing a lot of extra water, Welvaert said. Doyle Rice, USA TODAY, 3 May 2023 Madeline Heim is a Report for America corps reporter who writes about environmental issues in the Mississippi River watershed and across Wisconsin. Madeline Heim, Journal Sentinel, 2 May 2023 Thanks to a watershed that doesn’t produce much pollution, Lake George’s waters are clear, clean, and safe to swim in. Lydia Mansel, Travel + Leisure, 29 Apr. 2023 The murder of Emmett Till was a watershed in United States race relations. Margalit Fox, New York Times, 27 Apr. 2023 The data comes from the March 28 update of a monthly publication forecasting seasonal runoff from the state’s major watersheds. Jack Lee, San Francisco Chronicle, 5 Apr. 2023 Between the two watersheds, there’s about 1.1 million acre-feet massed and ready to pour toward the desert. Brandon Loomis, The Arizona Republic, 1 Mar. 2023 With global warming, average temperatures across the upper watershed — where most of the river’s flow originates — have risen about 3 degrees since 1970. Los Angeles Times, 5 Feb. 2023 In recent months, Gov. Spencer Cox closed the lake’s watershed to new water rights. Leia Larsen, The Salt Lake Tribune, 5 Jan. 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'watershed.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1764, in the meaning defined at sense 1a

Time Traveler
The first known use of watershed was in 1764


Dictionary Entries Near watershed

Cite this Entry

“Watershed.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/watershed. Accessed 7 Jun. 2023.

Kids Definition


wa·​ter·​shed ˈwȯt-ər-ˌshed How to pronounce watershed (audio)
: a dividing ridge (as a mountain range) separating one drainage area from others
: the area that drains into a river or lake

More from Merriam-Webster on watershed

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