What is the name to differentiate between parts of an app that have different types of users in each part?

Question

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.

Answer 1

I typically refer to the back-end of my web apps as the "administrative interface". Users understand that an interface is a specific view different from others, but can work with the same information. The front-end is the "public interface". There's never been a misunderstanding.

I should point out many of my clients often say "admin site" and "public site", which is technically incorrect, but seems to make the most sense to them conceptually.

I think "domain" or "tier" are also good suggestions (@LMC) since they imply security levels. I reserve the word "role" for security and not UI.