watershed

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noun wa·ter·shed \ˈwȯ-tər-ˌshed, ˈwä-\

Definition of watershed

1a : divide 2ab : a region or area bounded peripherally by a divide and draining ultimately to a particular watercourse or body of water
2 : a crucial dividing point, line, or factor : turning point

watershed

adjective

See watershed defined for English-language learners

See watershed defined for kids

watershed was our Word of the Day on 03/23/2017. Hear the podcast!

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 of watershed from the Web

Parasites, viruses and bacteria from feces can make their way into the watershed and lurk, invisible, until hikers slurp them up.

— sammy caiola, sacbee.com, "Mountain water may look clear, but don’t trust it", 4 July 2017
That’s why this case is indeed a watershed for Catholicism and Francis himself.

— andrew sullivan, Daily Intelligencer, "Cardinal Pell and the Vatican’s Day of Reckoning", 30 June 2017
Trump presented this as a watershed victory and went out to the plant to give a celebratory address.

— jack holmes, Esquire, "Wait, Trump Didn't Actually Save Those Carrier Jobs?", 23 June 2017
Its watershed drains 284 square miles in six Kentucky counties, and state officials are quick to point out what happens in all those counties — not just Jefferson — affects its water quality.

— james bruggers, The Courier-Journal, "How to kill a Louisville stream? Build a city around it", 22 June 2017
The Maumee runs through northwestern Ohio but it is fed by a watershed that reaches into Michigan and Indiana.

— keith matheny, Detroit Free Press, "State plan to combat algae in Lake Erie needs work, critics say", 18 June 2017
The construction work will take place Monday through Friday between 7 a.m. and 7 p.m., and is expected to last about four months, according to the watershed management.

— leslie johnson, ajc, "Atlanta installing water main along Peachtree Battle stretch", 16 June 2017
Miguel Lemus, head of the state’s Public Service Commission in Tijuana, known as CESPT, said his agency is currently working on repairing five sewage collectors, a priority for avoiding future spills into the Tijuana River watershed.

— sandra dibble, sandiegouniontribune.com, "Failing Tijuana coastal sewage treatment plant in line for $24.7 million overhaul", 6 June 2017
The Arab-Israeli war that took place in June of 1967 was undeniably a major watershed in modern Middle Eastern history and a fundamental inflection point in the Arab-Israeli conflict.

— aaron david miller, The Atlantic, "The Myths About 1967 That Just Won't Die", 2 June 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'watershed'. Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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."

First Known Use of watershed

1764

Other Geology Terms

anthracite, boulder, cwm, erratic, igneous, intrusive, mesa, sedimentary, silt, swale

WATERSHED Defined for English Language Learners

watershed

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noun

Definition of watershed for English Language Learners

: a time when an important change happens
: a line of hills or mountains from which rivers drain : a ridge between two rivers
: the area of land that includes a particular river or lake and all the rivers, streams, etc., that flow into it