- 海底捞月 hǎidǐlāoyuè last-tile win(mahjong) to complete one's hand on the last draw of the round
- 海底扩张说 hǎidǐkuòzhāngshuō seafloor spreading theorytheory of seafloor spreading in geology
- 海底捞 Hǎidǐlāo HaidilaoHaidilao, a hot pot restaurant chain founded in Sichuan in 1994
- 海底扩张 hǎidǐkuòzhāng seafloor spreadingseafloor spreading (geology)
- 海底椰 hǎidǐyē sea coconutcoco de mer or "sea coconut" (Lodoicea maldivica)
- 海底热泉 hǎidǐrèquán hydrothermal vent(marine geology) A hydrothermal vent on the seafloor.
- 海底轮 hǎidǐlún root chakramuladhara, the root or Saturn chakra, residing in the coccyx
