un·​der·​wa·​ter | \ ˌən-dər-ˈwȯ-tər How to pronounce underwater (audio) , -ˈwä- \

Definition of underwater

1 : lying, growing, worn, performed, or operating below the surface of the water underwater plants
2 : being below the waterline of a ship
3a : having, relating to, or being a mortgage loan for which more is owed than the property securing the loan is worth
b : having, relating to, or being a stock option for which the price of the option is higher than the current market value of the stock

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Other Words from underwater

underwater adverb

Synonyms for underwater


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Examples of underwater in a Sentence

underwater plants don't require as much light to grow as surface plants a vessel designed for underwater exploration
Recent Examples on the Web Sebens has been using an underwater remote operating vehicle to search debris that was pushed into the ocean. James Brooks, Anchorage Daily News, "Fourth day of searching begins for 2 missing in Haines as concern lingers over potential for more landslides," 5 Dec. 2020 Authorities have also used a submersible underwater vehicle with sonar to search for the boy in unspecified bodies of water. Kirk Mitchell, The Denver Post, "Gannon Stauch case: Concentrated, small search groups to look for boy Friday," 7 Feb. 2020 The realization felt like death, or like being underwater, but not in a peaceful way. Brontez Purnell, The Atlantic, "Early Retirement," 21 Jan. 2021 Models estimate that in just three decades, 95 percent of North Jakarta could be underwater. Matt Simon, Wired, "The Ongoing Collapse of the World's Aquifers," 19 Jan. 2021 Situated about 230 feet underwater, the wreck represented the deepest marine excavation ever attempted at the time of the first salvage attempt. Theresa Machemer, Smithsonian Magazine, "Who Owns the Art Recovered From Shipwrecks?," 29 Jan. 2020 Beach and underwater detectors tend to be more robust and rust resistant to help fight corrosion from sea air and salt water. Gabrielle Hondorp, Popular Mechanics, "The 5 Best Metal Detectors for Beginners," 28 June 2020 Based on the differences in mass between the underwater and unweathered Lego bricks, the study authors project that the toys could last anywhere from 100 to 1,300 years in the marine environment. Brigit Katz, Smithsonian Magazine, "Lego Pieces Could Last for 1,300 Years in Marine Environments," 24 Mar. 2020 That superlative belongs to Hawaii’s Mauna Kea, which is largely underwater. Washington Post, "It’s official: Mount Everest just got a little bit higher," 8 Dec. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'underwater.' 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 underwater

1627, in the meaning defined at sense 1

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Time Traveler for underwater

Time Traveler

The first known use of underwater was in 1627

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Statistics for underwater

Last Updated

27 Feb 2021

Cite this Entry

“Underwater.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/underwater. Accessed 5 Mar. 2021.

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More Definitions for underwater



English Language Learners Definition of underwater

: located, used, done, or happening below the surface of water


un·​der·​wa·​ter | \ ˈən-dər-ˈwȯ-tər How to pronounce underwater (audio) , -ˈwä- \

Kids Definition of underwater

 (Entry 1 of 2)

: lying, growing, worn, performed, or operating below the surface of the water an underwater cave underwater somersaults


un·​der·​wa·​ter | \ ˌən-dər-ˈwȯ-tər How to pronounce underwater (audio) , -ˈwä- \

Kids Definition of underwater (Entry 2 of 2)

: under the surface of the water I like to swim underwater.



Legal Definition of underwater

1 : owing more on a mortgage loan than the property securing the loan is worth underwater homeowners
2 : being or relating to a mortgage loan in which more is owed than the property securing the loan is worth underwater mortgages underwater properties

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