from
The Collaborative International Dictionary of English v.0.48
Knapsack \Knap"sack`\, n. [D. knapzak; knappen to eat + zak a
bag. See {Knap}, v. t., and {Sack}.]
A case of canvas, leather, nylon, or other sturdy fabric,
fitted with straps, for carrying on the back the food,
clothing, or other supplies for a soldier or a traveler; as,
to hike up the mountain with lunch in a knapsack.
[1913 Webster +PJC]
And each one fills his knapsack or his scrip
With some rare thing that on the field is found.
--Drayton.
[1913 Webster]