What do they call book bags in the UK?

In the UK, book bags are commonly referred to as school bags or rucksacks. The term "book bag" is less commonly used in the UK compared to the US. School bags in the UK typically consist of a large compartment for books and other school supplies, along with additional compartments or pockets for smaller items such as lunch boxes or water bottles. They are designed to be carried on the back and are often made from durable materials such as canvas or nylon.