Zoom Out decreases the magnification of the model in the active view, so that the new view area is ~111% of the old view area.
Zoom Out is useful when you quickly want to zoom out on the model. You can keep selecting Zoom Out as many times as necessary. If you want to restore the entire model to view, then you may want to use the Zoom All option, rather than Zoom Out.
Zoom Out is available in:
The Zoom sub-menu of the View menu,
The Zoom toolbar,
The F4 function key,
The End key.
If you have a mouse with a wheel you can zoom out by moving the wheel backward.