Pronunciation: (bak'pak"),[key] —n. 1. a pack or knapsack, often of canvas or nylon, to be carried on one's back, sometimes supported on a lightweight metal frame strapped to the body.
2. a piece of equipment designed to be used while being carried on the back.
—v.i. to go on a hike, using a backpack: We went backpacking in the Adirondacks.
—v.t. to place or carry in a backpack or on one's back.