What is the best practises to set admin page url of web application or website?

I would like to know how set or structure website admin page URL. For instance: If i'm creating any type of website or web application, i would go with URL like this: websitename.com/admin. I'm not saying this is bad way of doing things but i don't feel like this is the best way to go from the privacy point of view. I have heard that there is way that separate these two modules(Admin page and Pages which available to end users) from each other. Different URL for Admin Panel and different URL for end users.

P.s: I'm not asking for CMS based websites or web applications.