Difference between admin and user admin

Question

What is the difference bewteen the Admin and User Admin concepts?

You can find them in different places, like:

• _user_admin_menu or is_user_admin()
• _admin_menu or is_admin()

I did not find a clear explanation for them, and each explanation for itself does not make it clear neither. The documentation says:

is_user_admin()

Whether the current request is for a user admin screen.

is_admin()

Whether the current request is for an administrative interface page.

Since admin screen and administrative interface page are quite similar concepts to me, I am confused.

Answer 1

A "user admin screen" (or interface page) is a page in wp-admin for managing users. An "admin screen" (or interface page) is any page in wp-admin, which includes user admin screens but also screens for managing other types of data.