seabed vs sea bottom

seabed and sea bottom both are nouns.

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

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

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

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