It’s a way of grouping items together in a logical way so that your module is easy to navigate. In Rust a module is simply a container for zero or more items. When creating modules and submodules you use mod to declare them so you can utilise them in your current. It can be confusing when starting out in Rust to understand mod and how it differs over use. The Rust documentation resources are really well written and you can see more information of everything discussed about use in the reference pages here.
