An admin role is a permission set, usually specific to a feature, granting rights to administer that feature only:
For example, the admin role Address Lists, as shown in the screenshot, grants the administrator within that role the right to manage address lists, including global and offline address lists. The role Data Loss Prevention lets the admin manage DLP settings.
An admin role group is a collection of admin roles. Administrators are assigned to admin role groups, rather than having specific admin roles assigned to them:
For example, the admin role group Discovery Management contains the admin ...