# undersea

/ˌəndɝˈsi/ (US) · /ˌʌndəsˈiː/ (UK) · CEFR B2 · Adjective

Source: https://englishreference.com/word/undersea
Updated: 2026-05-20

## Definition

located or happening below the surface of the sea. You use this to describe things like cables, animals, or structures that are deep in the ocean.

For teachers: situated or occurring beneath the surface of the sea. Often used to describe infrastructure, marine life, or geological features found in the ocean depths.

## Examples

- The divers explored the undersea world of coral reefs.
- Engineers installed a high-speed undersea cable to connect the two islands for better internet service.
- The documentary provides a fascinating look at the undersea ecosystem, revealing how life thrives in the extreme pressure and darkness of the deep ocean floor.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.