While designing a Web Application in ASP.Net, I usually split the project in 2 parts, the back-end (the admin part) and the front-end (the visitors/SEO part). Let's say that my visitors can login on the website and will do a lot of tasks, like fill profile, send messages, etc.
That part (authenticated user) looks for me a differente "layer" between Front-end and Back-end, and is somewhat hard define if is front-end (why visitors/users will handle it, but no admins) or if it is back-end (why the user will proactively make changes in database, like admins, but with less rights).
There is a term to define that "layer", like "mid-end" or I'm floating my mind to wrong places here and there is a clear definition to this (unknown to me)?