A backpack is a type of bag that is designed to be carried on a person's back. It typically features two shoulder straps and a main compartment for storing items. Backpacks are commonly used by students to carry books and school supplies, as well as by hikers and travelers for outdoor activities and trips. They come in various sizes, styles, and materials to suit different needs. Backpacks often include additional pockets and compartments for organization, making it easier to access smaller items like water bottles, snacks, or electronic devices. Some backpacks are designed with specific features, such as padded straps for comfort or waterproof materials for protection against the elements. Popular brands include North Face, Osprey, and JanSport.