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deep sea

deep sea

6 3.6
The deepest parts of the ocean far below the surface where little or no sunlight reaches
  • noun
  • /dip si/
translation icon : mar profundo
  • Indeed, it has been estimated that 80-90% of creatures in the deep sea are bioluminescent.
  • deep sea environment

And for me, it's clearly the deep sea, the zoology that's down there.

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Examples

  • Finding a mate occurs in the unlikeliest of places, as blob sculpins and deep-sea octopuses attest.

    Academic text (2004)
  • Why don't we have a deep sea base yet?

  • I will share a secret: I love the sea critters, especially the deep sea ones.

    Blog text (18)
  • There had been earlier attempts to pump carbon dioxide into the deep sea.

    Fiction book (1998)
  • So it's interesting that they are so prevalent in the deep sea where sunlight is weak or never reaches.

    Blog text (13)
  • Everyone is aware of the magnitude of the deep-sea microbial environment.

    Academic text (2012)
  • The ship's high-tech robotic submersible will act as their eyes and arms in the deep sea.

  • "In the deep sea," Van Dover reflects, "there live creatures of extraordinary beauty, exquisitely adapted to extraordinary environments."

    Academic text (2010)
  • The researchers discovered new creatures living in the deep sea that glow in the dark.

  • Many scientists believe that the deep sea holds secrets about Earth's history and climate change.

Synonyms

deep
vsdeep sea
6 7.4

A very low, steep part of the ocean floor

is about dark ocean zones far below the surface rather than a floor feature
depths
vsdeep sea
1 3.9

The lowest parts of a place or a feeling

is about the ocean's low light zones rather than a general metaphor
deepwater
vsdeep sea
1 4.0

The deep part of a sea or lake away from the shore

is the ocean's lower zones where little or no sunlight penetrates

Antonyms

14 3.3

A part of a river or sea that is not deep

How Deep

hadal
  • Specialized
9.9
abyssal zone
  • Specialized
9.9
deep sea
6 3.6
continental shelf
  • Specialized
4 5.5
coastal
129 2.4

Surface Forms

deep sea singular
deep seas plural

Morphology

deep + sea

The meaning 'the deeper parts of the ocean' is directly and transparently derived from combining 'deep' (extending far down) with 'sea' (a large body of saltwater); the adjective simply specifies a depth-related subpart of the sea. This straightforward adjective+noun composition is cross-linguistically common and predictable, so a B1 learner who knows both constituents will readily infer the MWE's meaning.

Etymology

The noun deep sea comes from the simple image of the very deep part of the sea where you cannot see the bottom. Sailors and scientists used the phrase for water 'far below the surface' where little or no 'sunlight' reaches, so deep sea now means the lowest, dark parts of the ocean.