rusk vs zwieback

rusk and zwieback both are nouns.

Word	Noun	Adjective	Verb	Adverb
rusk	Yes	No	No	No
zwieback	Yes	No	No	No

As nouns, rusk and zwieback are synonyms defined as:

rusk and zwieback: slice of sweet raised bread baked again until it is brown and hard and crisp

Other synonyms of rusk include Brussels biscuit, twice-baked bread.

rusk (noun)	zwieback (noun)
slice of sweet raised bread baked again until it is brown and hard and crisp	slice of sweet raised bread baked again until it is brown and hard and crisp