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Synonyms

undersea

American  
[uhn-der-see] / ˈʌn dərˌsi /

adjective

  1. located, carried on, or used under the surface of the sea.

    undersea life.


adverb

  1. underseas.

undersea British  
/ ˈʌndəˌsiː /

adjective

  1. below the surface of the sea

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of undersea

First recorded in 1605–15; under- + sea

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.

See Examples For:

The city's coastline also allows undersea cables to link Visakhapatnam to South Africa and Australia, "positioning Andhra Pradesh as India's third major subsea hub", Smith said.

From Barron's ● Oct. 11, 2026

By placing bets on acquiring a full fleet of uncrewed systems, including aerial and undersea drones, Taiwan hopes to build defensive capabilities intended to make its far more powerful adversary think twice about invading.

From The Wall Street Journal ● Aug. 27, 2026

Prosecutors identified the man only as trained scuba diver Vladimir Z, however he is understood to be Volodymyr Zhuravlyov, who was arrested in Poland in 2025 over the undersea plot.

From BBC ● Aug. 19, 2026

He specifically instructed NOAA, which is under his purview, to take offshore oil production, pipeline maintenance, spaceport infrastructure, desalination projects and undersea cables into consideration, citing national priorities and economic interests.

From Los Angeles Times ● Aug. 11, 2026

The grass swayed and rustled around her like the tentacles of a gigantic undersea anemone.

From "The Son of Neptune" by Rick Riordan

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