haversack vs packsack

haversack and packsack both are nouns.

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

As nouns, haversack and packsack are synonyms defined as:

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

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

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