undersea

1 of 2

adjective

un·​der·​sea ˌən-dər-ˈsē 

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

undersea

2 of 2

adverb

variants or underseas

ˌən-dər-ˈsēz 

: under the sea : beneath the surface of the sea

photographs taken undersea

Examples of undersea in a Sentence

Adjective

They are conducting undersea research.

Recent Examples on the Web

Adjective

The sea passage is also believed to be sitting atop vast undersea deposits of oil and gas. — ABC News, 26 July 2026

The step will reinforce L3Harris’ growing role in supporting America’s undersea warfare capabilities. — Prabhat Ranjan Mishra, Interesting Engineering, 26 July 2026

In 2006, the Zale Parry Scholarship was established by the Academy of Underwater Arts & Sciences to support students pursuing careers in undersea exploration, marine conservation, hyperbaric medicine and diving technology. — Mike Barnes, HollywoodReporter, 23 July 2026

Tony Romeo, the CEO of the undersea exploration firm Deep Sea Vision, had been speaking to Matthews for some time about the possibility of helping to find the aircraft if one of his ships was ever in the area. — Landon Mion, FOXNews.com, 22 July 2026

Word History

First Known Use

Adjective

1613, in the meaning defined at sense 1

Adverb

1645, in the meaning defined above

Rhymes for undersea

• abc
• absentee
• addressee
• adoptee
• allottee
• amphorae
• amputee
• apc
• apogee
• appointee
• assessee
• assignee

Kids Definition

undersea

adjective

un·​der·​sea

ˈən-dər-ˈsē

1

: being or carried on under the sea or under the surface of the sea

undersea oil deposits

undersea warfare

2

: designed for use under the surface of the sea

undersea fleet