backpack vs back pack

backpack and back pack both are nouns.

Word	Noun	Adjective	Verb	Adverb
backpack	Yes	No	Yes	No
back pack	Yes	No	No	No

As nouns, backpack and back pack are synonyms defined as:

backpack and back pack: a bag carried by a strap on your back or shoulder

Other synonyms of backpack include haversack, knapsack, packsack, rucksack.

backpack (noun)	back pack (noun)
a bag carried by a strap on your back or shoulder	a bag carried by a strap on your back or shoulder

backpack (verb)	back pack (verb)
hike with a backpack