- The definition of a knapsack is a bag for carrying supplies that is worn on the back.
An example of a knapsack is a schoolbag.
A woman wearing a backpack or knapsack.
Origin of knapsackDutch knapzak ; from knappen (see knap) + zak, a sack
Origin of knapsackProbably Low German Knappsack : knappen, to bite (probably of imitative origin) + Sack, bag (from Middle Low German sak, from Old High German sac, from Late Latin saccus; see sack1).
- (US) A case of canvas or leather, for carrying items on the back.
(third-person singular simple present knapsacks, present participle knapsacking, simple past and past participle knapsacked)
- To go hiking while burdened with a knapsack, usually overnight (longer.)
- My sleeping bag fell off my backpack into the water, while we were knapsacking up the mountain.