estuary

American  

[es-choo-er-ee] / ˈɛs tʃuˌɛr i /

noun

• estuaries
  plural

1. that part of the mouth or lower course of a river in which the river's current meets the sea's tide.

2. an arm or inlet of the sea at the lower end of a river.

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estuary British  

/ ˈɛstjʊərɪ /

noun

1. the widening channel of a river where it nears the sea, with a mixing of fresh water and salt (tidal) water

2. an inlet of the sea

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estuary Scientific  

/ ĕs′cho̅o̅-ĕr′ē /

1. The wide lower course of a river where it flows into the sea. Estuaries experience tidal flows and their water is a changing mixture of fresh and salt.

2. An arm of the sea that extends inland to meet the mouth of a river.

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estuary Cultural  

1. A wide body of water formed where a large river meets the sea. It contains both fresh and salt water.

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Other Word Forms

Derived Forms

• estuarial
  adjective

Inflected Forms

Nouns

• estuaries
  plural

Etymology

Origin of estuary

First recorded in 1530–40; from Latin aestuārium “channel, creek, inlet,” from aestu(s) “fire, heat, tide” + -ārium -ary

Explanation

An estuary is the place in the water where a tide and a river current meet, like the estuary at New York Harbor, where the Hudson River meets the Atlantic Ocean. Estuary, pronounced "ES-choo-air-ee," comes from the Latin word aestuarium, meaning "a tidal marsh or opening." The calm waters of an estuary, where the mouth of a river connects with the open sea and fresh water mixes with salty ocean water, makes the perfect home for many species of aquatic plants and animals. Chesapeake Bay and Puget Sound are estuaries.

Example Sentences

See Examples For:

estuary estuaries

But these sites also come with dangers, as demonstrated by the massive Moss Landing battery fire in January 2025, which prompted the evacuation of about 1,500 residents and deposited heavy metals in a nearby estuary.

From Los Angeles Times ● Sep. 25, 2026

Around river mouths, the distance extends to 500 meters from the estuary.

From Science Daily ● Sep. 10, 2026

In Foynes village across the estuary from the refinery, where a port handles its exports, local businessman John Cassels said the dilemma was clear.

From Barron's ● Jul. 24, 2026

According to Williams, Y Foryd area and the Afon Seiont estuary were "great places for him", as he feeds in a similar way to a Little egret, searching for and eating small fish.

From BBC ● Jun. 9, 2026

That river, that chalk quarry, that estuary in the glimmering night—familiar landmarks.

From "Code Name Verity" by Elizabeth Wein

The researchers examined more than 2,580 MHWs recorded across 20 U.S. estuaries over two decades.

From Science Daily ● Sep. 30, 2026

Using long term observations from 20 U.S. estuaries, the researchers developed a way to measure total heat exposure by viewing marine heatwaves as part of broader warming episodes rather than as isolated events.

From Science Daily ● Sep. 30, 2026

Sewage discharges, runoff of fertilisers and manures from farms and wastewater from industry can all increase nutrient levels in rivers and estuaries.

From BBC ● May 2, 2026

Thousands of water tests to identify potential harmful pollution in rivers, lakes and estuaries in England have been cancelled in the last three months due to staff shortages, the BBC has learned.

From BBC ● Jul. 23, 2025

The inshore waters —the bays, the sounds, the river estuaries, the tidal marshes — form an ecological unit of the utmost importance.

From "Silent Spring" by Rachel Carson

Related Words

• inlet
• waterway