knap·sack
noun/ˈnæpsæk/
/ˈnæpsæk/
(old-fashioned or North American English)- a small rucksack
小背包 - He had walked into the school yard that morning with his knapsack on his back and his lunchbox in his hand.
那天早上，他背着小背包拿着午餐盒走进了校园。
Word Originearly 17th cent.: from Middle Low German, from Dutch knapzack, probably from German knappen ‘ to bite’ + zak ‘sack’. - He had walked into the school yard that morning with his knapsack on his back and his lunchbox in his hand.