海底 (hǎi dǐ) means “seabed; seafloor; bottom of the ocean”. It is an HSK 6 Chinese word in the HSK 3.0 vocabulary.
Practice each character:
科学家在海底发现了新物种。
Kēxuéjiā zài hǎi dǐ fāxiàn le xīn wùzhǒng.
Scientists discovered new species on the seabed.
Updated: 2026-07-18