Look up knapsack in Wiktionary, the free dictionary.
The word knapsack can refer to:
- a backpack
- Knapsack, Germany, a locality of Hürth, Rhine-Erft district, North Rhine-Westphalia
- the knapsack problem, a math problem
- the subset sum problem, a special case of the above
- Naccache-Stern knapsack cryptosystem, a cryptosystem based on the knapsack problem
- Knapsack (band), an American band
- "Knapsack!", an episode of Aqua Teen Hunger Force