[back.pack] n (1914) 1 a: a load carried on the back b: a camping pack (as of canvas or nylon) supported by a usu. aluminum frame and carried on the back
2: a piece of equipment designed for use while being carried on the back
[2]backpack vt (1927): to carry (food or equipment) on the back esp. in hiking ~ vi: to hike with a backpack -- back.pack.er n