Knap"sack` (?), n. [D. knapzak; knappen to eat + zak a bag. See Knap, v. t., and Sack.]
A case of canvas or leather, for carrying on the back a soldier's necessaries, or the clothing, etc., of a traveler.
And each one fills his knapsack or his scrip
With some rare thing that on the field is found.
© Webster 1913.