bathyal district vs seabed

bathyal district and seabed both are nouns.

Word	Noun	Adjective	Verb	Adverb
bathyal district	Yes	No	No	No
seabed	Yes	No	No	No

As nouns, seabed is a hypernym of bathyal district; that is, seabed is a word with a broader meaning than bathyal district:

bathyal district: the steep descent of the seabed from the continental shelf to the abyssal zone
seabed: the bottom of a sea or ocean

Other hypernyms of bathyal district include Davy Jones's locker, Davy Jones, ocean bottom, ocean floor, sea bottom, sea floor.

bathyal district (noun)	seabed (noun)
the steep descent of the seabed from the continental shelf to the abyssal zone	the bottom of a sea or ocean