深海

1. Origins, structure, and basic meaning

• Structure: 深海 is read as しんかい and is a noun for the deep sea or deep ocean, where little sunlight reaches.
• Basic usage: Terrain appears in 深海の地形, while habitat appears in 深海に暮らす.

2. Common pitfalls and similar expressions

• Depth and environment
  • It emphasizes a deep-water environment with conditions such as intense pressure, not merely water far from shore.
• Difference from 沖
  • 沖 locates the sea away from shore, while 深海 identifies the sea by depth.