from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A bag made of sturdy material and furnished with shoulder straps, designed for carrying articles such as camping supplies on the back.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A case of canvas or leather, for carrying items on the back.
- v. To go hiking while burdened with a knapsack, usually overnight (or longer.)
from the GNU version of the Collaborative International Dictionary of English
- n. A case of canvas, leather, nylon, or other sturdy fabric, fitted with straps, for carrying on the back the food, clothing, or other supplies for a soldier or a traveler.
from The Century Dictionary and Cyclopedia
- n. A case or bag of leather or strong cloth for carrying a soldier's necessaries, closely strapped to the back between the shoulders; hence, any case or bag for similar use.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a bag carried by a strap on your back or shoulder
Probably Low German Knappsack : knappen, to bite (probably of imitative origin) + Sack, bag (from Middle Low German sak, from Old High German sac, from Late Latin saccus; see sack1).(American Heritage® Dictionary of the English Language, Fourth Edition)