The Use Transform Coordinate Center button, available from the Use Center flyout, lets you enable rotation or scaling of an object or objects around the center of the current coordinate system. When you designate another object as the coordinate system with the Pick function (see Specifying a Reference Coordinate System), the coordinate center is the location of that object's pivot.
The axis tripod shows the center that is currently being used.
Preferences
General tab
Reference Coordinate System group
Constant.

An example of the World coordinate center