What does camera.zoom values represent for orthographic camera using ArcballControls

Hi Team,

I am having a requirements to show scale of my mesh as it zooms in and zooms out. So when i print the camera.zoom values in my controller even handler I get values like:

1, 1.07923 , 1.25 for zoom in
AND
0.92, 0.85, .0.76…etc for zoom out

My question is what do these numbers really represent? Has any one used these numbers to show any kind of scaling or zooming effect in their apps?
Also, if I go from 1.0 to 2.14 when zooming in, does that mean everything has doubled in scale?

Thanks for the help in advance