Terminology
The word backpack was coined in the United States in the 1910s. moneybag and packsack were used before; they now occur mainly as regionalisms. The word rucksack is a German loanword mainly used in the UK and in the US Army: in German 'der Rücken' means 'the back' (the part of the body), and Sack for bag. The name Rucksack is cognate with Danish Rygsæk, Norwegian Ryggsekk, Dutch Rugzak, Afrikaans Rugsak and Swedish Ryggsäck. Alternative names include Haversack, and in German language called Kraxe (in 19th century the term kraxeln was used for climbing). (The term "haversack" more properly describes a small cloth bag on a strap worn over one shoulder, and used to carry one or more "havers" or havercakes or oatcakes.)
Backpacks can often simply be referred to as "packs", especially in outdoors contexts; though sometimes ambiguous compared to other bags such as saddlebags and duffel bags, context is generally sufficient for identification.
A bodypack is a backpack fitted with pocket(s) that are suspended on the wearer's front side (chest) and loaded in such a way that the load in the front and the load in the back are about equal. The majority of the load on a bodypack is carried by the hips.
The ideal load carrying system should not disturb the wearer's natural posture, balance and movement of the body. The load must be dispersed onto the skeletal structure in a balanced way, and should not produce forces on the body forward, aft, right, or left.
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