名詞 knapsack:

1. a bag carried by a strap on your back or shoulder
   同義詞：backpack, back pack, packsack, rucksack, haversack

1. After a short rest, they took up their knapsacks and went on.
   休息了一會兒之后，他們又背起背包上路了。

knap.sack

n.（名詞）
A bag made of sturdy material and furnished with shoulder straps, designed for carrying articles such as camping supplies on the back.
背包：由結(jié)實的材料制成的有肩背帶的背包，用于背如野營用品等物品

來源：
Probably Low German Knappsack
可能為 低地德語 Knappsack
knappen [to bite] [probably of imitative origin]
knappen [咬] [可能源于擬聲詞]
Sack [bag] from Middle Low German sak from Old High German sac from Late Latin saccus * see sack
Sack [包] 源自 中古低地德語 sak 源自 古高地德語 sac 源自 后期拉丁語 saccus *參見 sack