Rucksack
A rucksack is a backpack, literally a bag worn or carried on one’s back. Usually this has two straps over the shoulders and possibly one around the waist, and sometimes an internal frame for rigidity. Alternative English words include knapsack, backpack, haversack, and just plain pack. Other carrying devices have also emerged in recent years with names such as manbags, bumbags, waistpacks, shoulder bags, bodypacks, and courier bags.
The term Rucksack seems to have expanded in UK English from the middle of the twentieth century, possibly due to the wider popularity of mountaineering and mountaineers in German-speaking countries, or due to standardisations and translations across nations participating in NATO. Or possibly younger people just liked the term better, but backpacker remains the predominant noun used in English to describe a person travelling with a pack on their back.