n. a bag carried on the back, supported by straps looped over the shoulders. Syn. -- knapsack; rucksack; haversack. [ WordNet 1.5 ]
v. i. to hike while carrying a backpack; -- often used in the form go backpacking; as, to backpack through the forest. [ PJC ]
n. one who backpacks; as, two backpackers were mauled by bears in Yellowstone this week. [ PJC ]