watershed

noun

wa·​ter·​shed ˈwȯ-tər-ˌshed How to pronounce watershed (audio)
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."        

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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
For example, salt can release nitrogen or phosphorus from sediments in a watershed, which act as nutrients for plants—potentially leading to an overgrowth of algae and bacteria in the system, Kaushal said. Ars Technica, 19 Mar. 2025 Maryland is targeting five of its ailing watersheds for a concentrated push to restore them — but the state’s budget crisis has put funding for the effort in doubt. Timothy Wheeler, Baltimore Sun, 17 Mar. 2025 Just because an entire watershed is highlighted doesn’t mean the wolf or wolves roamed throughout the entire area or are still there, according to state wildlife officials. Katie Langford, The Denver Post, 27 Feb. 2025 The basin, which is home to Ash Meadows, is a vast desert watershed that feeds the Amargosa River. Meg Bernhard, New York Times, 24 Jan. 2025 See All Example Sentences for watershed

Word History

First Known Use

1764, in the meaning defined at sense 1a

Time Traveler
The first known use of watershed was in 1764

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Cite this Entry

“Watershed.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/watershed. Accessed 24 Mar. 2025.

Kids Definition

watershed

noun
wa·​ter·​shed ˈwȯt-ər-ˌshed How to pronounce watershed (audio)
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

More from Merriam-Webster on watershed

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