underwater

American  

[uhn-der-waw-ter, -wot-er] / ˈʌn dərˈwɔ tər, -ˈwɒt ər /

adjective

1. existing or occurring under water.

2. designed to be used under water.

3. located below a ship's waterline.

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adverb

1. beneath the water.

   to travel underwater.

noun

1. the water beneath the surface.

   cold currents in the underwater.

2. underwaters, the depths, as of a sea, lake, etc.

underwater British  

/ ˈʌndəˈwɔːtə /

adjective

1. being, occurring, or going under the surface of the water, esp the sea

   underwater exploration

2. nautical below the water line of a vessel

3. (of a stock option or other asset) having a market value below its purchase value

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adverb

1. beneath the surface of the water

Etymology

Origin of underwater

First recorded in 1620–30; under- + water

Example Sentences

Firms’ margins would be pummeled and consumer wage growth dragged underwater.

From Barron's • Apr. 2, 2026

Don’t miss the Tropical Rainforest Aviary for free-flight birds or the Arctic Passage, where you can watch polar bears and seals swim underwater.

From Salon • Mar. 31, 2026

Seama explains, "The underwater location allows us to implement systematic, large-scale surveys."

From Science Daily • Mar. 29, 2026

This week it says it has hit weapons and naval cruise-missile production sites in Tehran, an underwater research center in Isfahan used to manufacture submarines, and an explosive-materials production site in Isfahan.

From The Wall Street Journal • Mar. 26, 2026

Polar bears were great swimmers, but they couldn’t breathe underwater.

From "Two Degrees" by Alan Gratz

Related Words

• submerged
• undersea