1.
seabed, ocean floor, bottom of the sea
The ground at the bottom of the ocean or sea. Used in scientific, geographic, and descriptive contexts.
海底にサンゴが広がっている。
Coral spreads across the seabed.
海底トンネルで二つの島がつながった。
The two islands were connected by an undersea tunnel.
調査チームが海底火山の活動を観測している。
The research team is observing undersea volcanic activity.
USAGE:
Frequently used as a noun modifier: 海底トンネル (undersea tunnel), 海底火山 (submarine volcano), 海底ケーブル (submarine cable).
Do not confuse with the homophones 改定 (revision of rules/rates) or 改訂 (revision of text), which use different kanji.
COMMON COLLOCATIONS:
- 海底トンネル: undersea tunnel
- 海底火山: submarine volcano
- 海底ケーブル: submarine cable
- 海底探査: seabed exploration
- 深海の海底: deep-sea floor