bathyal district vs sea floor

bathyal district and sea floor both are nouns.

Word	Noun	Adjective	Verb	Adverb
bathyal district	Yes	No	No	No
sea floor	Yes	No	No	No

As nouns, sea floor is a hypernym of bathyal district; that is, sea floor 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
sea floor: 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, seabed.

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