bathypelagic Syllabification: (bath·y·pe·lag·ic)Pronunciation: /ˌbaTHəpəˈlajik/Definition of bathypelagic adjective Biology (of fish and other organisms) inhabiting the deep sea where the environment is dark and cold, approximately 3,300-9,800 feet (1,000-3,000 m) below the surface. bathypelagic in other Oxford dictionaries Definition of bathypelagic in the British & World English dictionary