backpack

A backpack, also called knapsack, schoolbag, rucksack, pack, booksack, bookbag, haversack, packsack, or backsack, is in its simplest frameless form, a fabric sack carried on one’s back and secured with two straps that go over the shoulders, and is used to carry goods from one place to another. It can feature an external or internal frame to transfer heavy loads off the user’s shoulders and onto their hips, reducing strain and increasing comfort on long hikes with heavy gear.