Digital Art Zone

In the Objects Attributes dialogue box there is an arrow next to Absolute Coordinates which reveal three other options.. Definition Coordinates, Set as Unity and Remove Shear.

I tried to find some info on these options in the manuals but could not find anything. Can someone throw some light on these options, what and when do we use them?

Thanks

Basically and subject to correction (LOL):
Definition coordinates shows the attributes offset from the center of the Bryce world (as opposed to their absolute world coords).
Set as Unity is essentially undo resize and rotate a prim to their original state.
Remove shear fixes resized prims that have been distorted using camera/object space cameras.

Thanks Dan for the explanation.