Axis Indicator

To show or hide the Axis Indicator:

3D View ribbon >> 3D Display >> Indicators >> Axis Indicator.
(In an external 3D window) Format >> Indicators >> Axis Indicator.

The Axis Indicator is a viewing aid and is used to show the relative orientation of X, Y and Z world coordinate axes in the active 3D window. It looks like this:

The orientation of the indicator is dynamically updated when the view direction is altered using any of the navigation controls. This indicator is only a viewing guide and resides in the bottom left corner of a 3D window.

Note: the Axis Controller, on the other hand, can change the view orientation.