haversack vs knapsack

haversack and knapsack both are nouns.

Word	Noun	Adjective	Verb	Adverb
haversack	Yes	No	No	No
knapsack	Yes	No	No	No

As nouns, haversack and knapsack are synonyms defined as:

haversack and knapsack: a bag carried by a strap on your back or shoulder

Other synonyms of haversack include back pack, backpack, packsack, rucksack.

haversack (noun)	knapsack (noun)
a bag carried by a strap on your back or shoulder	a bag carried by a strap on your back or shoulder