深海|しんかいshinkai[0]heiban (flat)

1. no-adjectivedeep sea; depths of the sea; ocean depths
   シーラカンスは深海しんかいに生息せいそくする。↗

   The coelacanth inhabits the deep sea.

• Related深みふかみNeutralA deep place in water, or depth; figuratively, profundity or a situation you can't escape. Neutral and broader than 「深海」, which is specifically the ocean depths.
• Related深淵しんえんWrittenAn abyss; written/formal prose that stresses bottomless depth, mostly figurative, as in 「絶望の深淵」.
• Antonym表層ひょうそうWrittenThe surface or outer layer; written/formal prose, opposed to the depths of 「深海」, as in 「海の表層」.
• Antonym浅海せんかいWrittenA shallow sea; written/formal prose, the opposite of 「深海」.

For the ocean depths use 「深海」, common in science, the news and daily life, as in 「深海魚」 or 「深海探査」; use 「深み」 for a deep place or depth in general, and 「深淵」 for a figurative, bottomless abyss. The opposites are 「浅海」 and 「表層」.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 深ふかい海うみ。主おもに、水深すいしん200m以上いじょうの深ふかさの海うみをいう。