toast vs zwieback

toast and zwieback both are nouns.

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

As nouns, zwieback is a hyponym of toast; that is, zwieback is a word with a more specific, narrower meaning than toast:

toast: slices of bread that have been toasted
zwieback: slice of sweet raised bread baked again until it is brown and hard and crisp

toast (noun)	zwieback (noun)
slices of bread that have been toasted	slice of sweet raised bread baked again until it is brown and hard and crisp
a drink in honor of or to the health of a person or event
a celebrity who receives much acclaim and attention
a person in desperate straits; someone doomed

toast (verb)	zwieback (verb)
make brown and crisp by heating
propose a toast to