ship biscuit vs pilot bread

ship biscuit and pilot bread both are nouns.

Word	Noun	Adjective	Verb	Adverb
ship biscuit	Yes	No	No	No
pilot bread	Yes	No	No	No

As nouns, ship biscuit and pilot bread are synonyms defined as:

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

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

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