Noun

1. A knapsack, sometimes mounted on a light frame, but always supported by straps, worn on a person’s back for the purpose of carrying things, especially when hiking, or on a student's back when carrying books.
2. A similarly placed item containing a parachute or other life-support equipment.

Verb

1. To hike and camp overnight in backcountry with one's gear carried in a backpack.
2. To engage in low-cost, generally urban, travel with minimal luggage and frugal accommodations.
3. To place or carry (an item or items) in a backpack.