Enligt Cambridge:
Bag noun ( CONTAINER ) /bæg/ n [C]
a soft container made out of paper or thin plastic, or a stronger container made of leather, plastic or other material, usually with a handle, in which you carry personal things or clothes or other things that you need for travelling
Rucksack noun /ˈrʌk.sæk/ n [C] (US usually backpack)
a large bag used to carry things on your back, used especially by walkers and climbers