Backpack +
![Backpack](https://files.ozbargain.com.au/t/21/1821.jpg?h=853c63d8)
A backpack (also called rucksack, knapsack, packsack, pack ) is, in its simplest form, a cloth sack carried on one's back and secured with two straps that go over the shoulders, but there can be exceptions. Lightweight types of backpacks are sometimes worn on only one shoulder strap.