ocean floor vs Davy Jones's locker

ocean floor and Davy Jones's locker both are nouns.

Word	Noun	Adjective	Verb	Adverb
ocean floor	Yes	No	No	No
Davy Jones's locker	Yes	No	No	No

As nouns, ocean floor and Davy Jones's locker are synonyms defined as:

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

ocean floor (noun)	Davy Jones's locker (noun)
the bottom of a sea or ocean	the bottom of a sea or ocean