That looks like it may be a piece of laminated glass with a frost look inter-layer.

Could anyone expand on what Echo etching means by "laminated glass with a frost look inter-layer" I am also trying to clarify what Opaque glass is - could this be it?

A laminated glass is a type of safety glass ( http://en.wikipedia.org/wiki/Laminated_glass). If this is laminated glass, then it may have a "frost" look in the middle layer of the glass.
Opaque glass means that you can not see anything through through it, as in it does not transmit any light through the glass. ( http://dictionary.reference.com/browse/opaque) This particular piece of glass door is not easy to tell from the picture whether it transmits light or not.

I just received the cabinet. You can see through it but blurred shapes and colors so it does transmit some light. I have some items that have frosted glass but they are on one side and you can feel the etching (or frosting). However, on this glass it is smooth on both sides so the frosting is in the middle layer. This is a lot nicer because something that has the frosted area on the outside can easily be scratched.