backpack
n. countable A2 Elementary US //ˈbækˌpæk// UK //bˈækpæk// back·pack
n. a bag with two straps that you wear on your back. It is very common for students or people who go hiking.
n. a bag with shoulder straps that allow it to be carried on the back. Often used for carrying school supplies, travel gear, or outdoor equipment.
I put my books in my backpack before school.
She packed her heavy backpack with enough water and snacks for the long hike up the mountain.
Modern ergonomic designs distribute the weight of a backpack across the hips and shoulders to prevent strain during extended periods of travel or trekking.
From back + pack.