seabed vs ocean bottom

seabed and ocean bottom both are nouns.

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

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

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

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