1. A sack containing necessaries of food and clothing, borne on the back by soldiers, travellers, &c.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• napsack,
• knasack,
• hoppsack,
• jnapsack,
• mnapsack,
• lnapsack,
• onapsack,
• inapsack,
• kbapsack,
• kmapsack,
• kjapsack,
• khapsack,
• knzpsack,
• knspsack,
• knapzack,
• knapsak,
• knapsac,
• kassack,
• snapsak,
• snapsakc

• knapik.

The adjective form of the word "knapsack" is "knapsackful".

The plural of the "knapsack" can be the "knapsacks".

The singular of the "knapsack" can be the "knapsack".