continental shelf vs sea floor

continental shelf and sea floor both are nouns.

Word	Noun	Adjective	Verb	Adverb
continental shelf	Yes	No	No	No
sea floor	Yes	No	No	No

As nouns, sea floor is a hypernym of continental shelf; that is, sea floor is a word with a broader meaning than continental shelf:

continental shelf: the relatively shallow (up to 200 meters) seabed surrounding a continent
sea floor: the bottom of a sea or ocean

Other hypernyms of continental shelf include Davy Jones's locker, Davy Jones, ocean bottom, ocean floor, sea bottom, seabed.

continental shelf (noun)	sea floor (noun)
the relatively shallow (up to 200 meters) seabed surrounding a continent	the bottom of a sea or ocean