backpack

n (esp US) = rucksack.

backbiter, backbiting, backbone, backchat, backcloth, backcomb (also tease), backdate, backdrop, backer, backfire, backgammon, background, backhand, backhanded, backhander, backing, backlash, backless, backlist, backlog, backpacker, backpacking, backrest, backscratcher, backset, backside, backslide, backsliding, backspace, backstage, backstroke, backtrack, backup, backward, backward(s), backwardness, backwards, backwards (also backward), backwash, backwater,