On a project I'm working on, I'm trying to find a noun to describe the different parts of the application dependent on user interface. There are three parts: super admin, admin and regular users. Each of these parts consist of modules, interfaces with users, interfaces with the other parts.
I've tried "sub-system", "module", "environment", "platform" but none of these really described what each of these parts of the system is. I need a noun that captures everything included within each part e.g. the super admin(?) enables the owner to manually add and edit content. Normally I would just use "module" but there are many modules within each part.