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

Kongsberg manufactures missiles, air defense systems and anti-drone solutions, among other things, and also produces technology for emerging defense markets such as underwater operations and space.

From The Wall Street Journal • Jun. 10, 2026

The reason we’re underwater is because most of us is hidden.

From Los Angeles Times • Jun. 1, 2026

With its increased military budget, Japan plans to invest in new surface-to-ship missiles and unmanned drones deployed on land and underwater.

From BBC • May 31, 2026

U.S. forces used underwater robots to clear it of mines in the weeks leading up to the operation.

From The Wall Street Journal • May 30, 2026

“The robots must be removing minerals from the underwater mountain. The floating structure must be the station where everything is controlled.”

From "The Wild Robot Protects" by Peter Brown

Related Words

• submerged
• undersea