es·​tu·​ary | \ˈes-chə-ˌwer-ē, ˈesh-\
plural estuaries

Definition of estuary 

: a water passage where the tide meets a river current especially : an arm of the sea at the lower end of a river

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Synonyms for estuary


arm, bay, bight, cove, creek [chiefly British], embayment, firth, fjord (also fiord), gulf, inlet, loch [Scottish]

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Did You Know?

A partly enclosed coastal body of water in which river water is mixed with seawater is called an estuary. An estuary is thus defined by salinity rather than geography. Many coastal features designated by other names are in fact estuaries (for instance, Chesapeake Bay). Some of the oldest continuous civilizations have flourished in estuarine environments (for example, the Tigris and Euphrates rivers, the Nile delta, and the Ganges delta). Cities such as London (Thames River), New York (Hudson River), and Montreal (St. Lawrence River) developed on estuaries and became important commercial centers.

Examples of estuary in a Sentence

the city sits on the shores of a deep estuary where the Hudson River meets the Atlantic Ocean

Recent Examples on the Web

Walleyes for Tomorrow assisted the estuary plan by providing $25,000 to the DNR to raise walleyes at the Lake Mills hatchery and stock them in the Milwaukee harbor. Paul A. Smith, Milwaukee Journal Sentinel, "Walleyes For Tomorrow organization makes push to restore fishery in Milwaukee River," 3 Mar. 2018 Environmentalists, Delta farmers and Sacramento Valley government officials say the WaterFix project would bring even more harm to the fragile estuary whose northern reaches start just a few miles south of Sacramento. Ryan Sabalow, sacbee, "Did Gov. Brown promise the Bay Area a new reservoir in exchange for Delta tunnels support? | The Sacramento Bee," 30 Apr. 2018 The annual closure is designed to protect juvenile white shrimp, which will begin making their big move into the lower estuaries sometime in the summer. Robert Rhoden,, "264 pound alligator gar caught in Texas river: report," 13 May 2018 Take the estuaries of California’s Monterey Bay, for example. National Geographic, "As Predators Rebound, You're More Likely to See Alligators at the Beach," 8 May 2018 In Oakland, the new bridge will be wider and taller than the old one, giving space for bike lanes and an underpass to connect Lake Merritt and the estuary for small boats. Kimberly Veklerov, San Francisco Chronicle, "New Oakland bridge expected to be two years late, millions over budget," 12 Jan. 2018 Federal biologists now estimate that as few as 17,000 may still survive in the estuary. Ryan Sabalow And Dale Kasler, sacbee, "These fish are at the heart of California's water debate. But extinction could be close," 1 June 2018 In the estuary, water began retreating, the high tide now pulled in the opposite direction, ebbing away from the edges. Shannon Tompkins, Houston Chronicle, "Bay food chain comes to life with tide change," 14 Apr. 2018 Algae that covers much of Lake Okeechobee has been growing and flowing through canals connecting the freshwater lake to sensitive estuaries on the east and west coasts of the state. Jennifer Kay,, "Blue-green algae, red tide soil beaches, threaten Florida tourism," 10 July 2018

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

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First Known Use of estuary

1538, in the meaning defined above

History and Etymology for estuary

Latin aestuarium, from aestus boiling, tide; akin to Latin aestas summer — more at edify

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Statistics for estuary

Last Updated

7 Nov 2018

Look-up Popularity

Time Traveler for estuary

The first known use of estuary was in 1538

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English Language Learners Definition of estuary

: an area where a river flows into the sea


es·​tu·​ary | \ˈes-chə-ˌwer-ē \
plural estuaries

Kids Definition of estuary

: an arm of the sea at the lower end of a river

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Comments on estuary

What made you want to look up estuary? Please tell us where you read or heard it (including the quote, if possible).


something that serves to warn or remind

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