pilot biscuit vs sea biscuit

pilot biscuit and sea biscuit both are nouns.

Word	Noun	Adjective	Verb	Adverb
pilot biscuit	Yes	No	No	No
sea biscuit	Yes	No	No	No

As nouns, pilot biscuit and sea biscuit are synonyms defined as:

pilot biscuit and sea biscuit: very hard unsalted biscuit or bread; a former ship's staple

Other synonyms of pilot biscuit include hardtack, pilot bread, ship biscuit.

pilot biscuit (noun)	sea biscuit (noun)
very hard unsalted biscuit or bread; a former ship's staple	very hard unsalted biscuit or bread; a former ship's staple