A backpack was a carrying device usually made from cloth and carried on a person's back. It can also be called a knapsack or pack.
In 2268 Cervantes Quinn was able to carry a shelter kit and some rope in a backpack. Bridget McLellan had carried a 5 megaton trilithium bomb and a medkit in her backpack. (VAN - Declassified novella: The Stars Look Down)