watershed
Americannoun
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Chiefly British. the ridge or crest line dividing two drainage areas; water parting; divide.
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the region or area drained by a river, stream, etc.; drainage area.
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Architecture. wash.
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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.
adjective
noun
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the dividing line between two adjacent river systems, such as a ridge
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an important period or factor that serves as a dividing line
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A continuous ridge of high ground forming a divide between two different drainage basins or river systems.
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The region enclosed by such a divide and draining into a river, river system, or other body of water.
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
Etymology
Origin of watershed
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.
Vocabulary lists containing watershed
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The Netherlands in 1899 hosted a watershed conference, on Laws and Customs of War on Land, that laid the foundation for modern laws of war.
From The Wall Street Journal • Jun. 19, 2026
Snowfall in the Gila River watershed was exceptionally scarce, leaving mountain snowpack at just 2 percent of the 1991-2020 March median.
From Science Daily • Jun. 18, 2026
“Overall, SpaceX going public is an important watershed moment for the broader tech sector in our view as this AI Revolution and data takes this next step forward,” Ives said.
From MarketWatch • Jun. 14, 2026
"Ilaiyaraaja's arrival was a watershed moment. It was an intervention by a person from an entirely different social and aesthetic background who had imbued a distinct aural soundscape," says TM Krishna, a celebrated Carnatic musician.
From BBC • Jun. 6, 2026
Although it was not a watershed moment, the current was beginning to shift, and as Bobby saw the accumulation of small advantages—a concept in chess described by Wilhelm Steinitz—he became optimistic, although not exhilarated.
From "Endgame" by Frank Brady
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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.