estuary

noun

es·​tu·​ary ˈes-chə-ˌwer-ē 

ˈesh-

plural estuaries

: a water passage where the tide meets a river current

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

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.

Synonyms of estuary

• bay
• firth

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

In North Carolina alone, 11,000 miles (17,702 kilometers) of canals drain peatlands before the water empties into coastal estuaries, Richardson said. — ABC News, 9 Sep. 2026

Amanvari also offers a variety of daily experiences, from horseback rides along the estuary at sunset to snorkeling and fishing off the coast. — Condé Nast, Condé Nast Traveler, 9 Sep. 2026

Once adopted, the state plan will set rules that determine how much water can be pumped out of the Delta and how much should stay in rivers and the estuary for fish and the environment. — Ian James, Los Angeles Times, 9 Sep. 2026

Rising Tide Explorers leads ecotours of the mangrove islands, estuaries, and marshes that surround Marco Island. — Tara Massouleh McCay, Southern Living, 4 Sep. 2026

Word History

Etymology

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

First Known Use

circa 1552, in the meaning defined above

Rhymes for estuary

• askari
• astbury
• azeri
• banbury
• barberry
• blackberry
• blueberry
• canary
• cranberry
• dentary
• dewberry
• dogberry

Kids Definition

estuary

noun

es·​tu·​ary ˈes-chə-ˌwer-ē 

plural estuaries

: a passage where the tide meets a river current

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

estuarine

ˈes-chə-wə-ˌrīn

adjective