ocean bottom vs seabed

ocean bottom and seabed both are nouns.

Word	Noun	Adjective	Verb	Adverb
ocean bottom	Yes	No	No	No
seabed	Yes	No	No	No

As nouns, ocean bottom and seabed are synonyms defined as:

Other synonyms of ocean bottom include Davy Jones's locker, Davy Jones, ocean floor, sea bottom, sea floor.

ocean bottom (noun)	seabed (noun)
the bottom of a sea or ocean	the bottom of a sea or ocean