OS X Yosemite: administrator
An administrator can add and manage other users, install apps, and change settings. The new user you create when you first set up your Mac is an administrator.
Your Mac can have multiple administrators. You can create new ones, and convert standard users to administrators.
Don’t set up automatic login for an administrator. If you do, someone could simply restart your Mac and gain access with administrator privileges. To keep your Mac secure, don’t share administrator names and passwords.