un·​der·​sea | \ ˌən-dər-ˈsē How to pronounce undersea (audio) \

Definition of undersea

 (Entry 1 of 2)

1 : being or carried on under the sea or under the surface of the sea undersea oil deposits undersea fighting
2 : designed for use under the surface of the sea an undersea fleet


\ ˌən-dər-ˈsēz How to pronounce undersea (audio) \
variants: or underseas

Definition of undersea (Entry 2 of 2)

: under the sea : beneath the surface of the sea photographs taken undersea

Examples of undersea in a Sentence


They are conducting undersea research.

Recent Examples on the Web: Adjective

Pinch your nose skin to see a few: Thin noodles of dead skin that eject from your pores like eels from undersea grottoes. Brennan Kilbane, Allure, "A Comprehensive Guide to the SkincareAddiction Subreddit," 5 Apr. 2019 Altmaier, a close ally of Chancellor Angela Merkel, stressed that Berlin wants to resolve its differences with the United States over plans for an undersea gas pipeline from Russia to Germany. Frank Jordans, The Seattle Times, "Germany, US seek to set aside spat over natural gas supplies," 12 Feb. 2019 Argentine Navy officials announced the discovery of the submarine on November 17th, sharing photographs taken of the sub by unmanned undersea vehicles. Kyle Mizokami, Popular Mechanics, "Lost Argentine Submarine Found One Year After Disappearance," 19 Nov. 2018 Eventually, the escape pod gives way to an undersea farm, which gives way to a fully autonomous base. Kyle Orland, Ars Technica, "Ars Technica’s best games of 2018," 24 Dec. 2018 From helicopter rides and submarines to the world’s first ultra-luxurious, fully-immersive undersea lounge, technology is bringing Antarctica and its charming neighbor islands to life like never before. Alex Postman, Condé Nast Traveler, "28 Places Our Travel Specialists Say You Should Go in 2019," 17 Dec. 2018 An undersea landslide capable of causing a tsunami could have caused some shaking, Caplan-Auerbach says, but probably not enough to have been felt by people nearby. Mary Beth Griggs, The Verge, "Deadly Indonesian tsunami was not caused by an earthquake," 23 Dec. 2018 Honorable Mentions / The Best of the Rest Omega Seamaster Diver 300M A rare diving watch that blends undersea functionality with city style. Michael Clerizo, WSJ, "The Best Watches of 2018," 18 Dec. 2018 This is possible because of undersea cables and satellite communications. Angela Chen, The Verge, "A retired Navy captain explains how drones will shape the future of war," 5 Dec. 2018

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

See More

First Known Use of undersea


1613, in the meaning defined at sense 1


1645, in the meaning defined above

Keep scrolling for more

Learn More about undersea

Statistics for undersea

Last Updated

20 Apr 2019

Look-up Popularity

Time Traveler for undersea

The first known use of undersea was in 1613

See more words from the same year

Keep scrolling for more

More Definitions for undersea



English Language Learners Definition of undersea

: found, done, or used below the surface of the sea


un·​der·​sea | \ ˈən-dər-ˈsē How to pronounce undersea (audio) \

Kids Definition of undersea

1 : being or done under the sea or under the surface of the sea an undersea volcano
2 : used under the surface of the sea an undersea vessel

Keep scrolling for more

More from Merriam-Webster on undersea

Rhyming Dictionary: Words that rhyme with undersea

Spanish Central: Translation of undersea

Nglish: Translation of undersea for Spanish Speakers

Comments on undersea

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


a strong desire or propensity

Get Word of the Day daily email!

Test Your Vocabulary

Challenging Vocabulary Quiz Returns!

  • stylized drawing of woman pole vaulting across gap to get trophy
  • Which is a synonym of fuliginous?
Name That Thing

Test your visual vocabulary with our 10-question challenge!


Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!