sea ladder vs sea steps

sea ladder and sea steps both are nouns.

Word	Noun	Adjective	Verb	Adverb
sea ladder	Yes	No	No	No
sea steps	Yes	No	No	No

As nouns, sea ladder and sea steps are synonyms defined as:

sea ladder and sea steps: (nautical) ladder to be lowered over a ship's side for coming aboard

sea ladder (noun)	sea steps (noun)
(nautical) ladder to be lowered over a ship's side for coming aboard	(nautical) ladder to be lowered over a ship's side for coming aboard