Intaglio is our word "du jour", and it refers to a process where a design is carved or pressed into a material as opposed to carving in relief. Think of a piece of jewelry with a sunken design (intaglio) versus a design that rises above the surface, like a cameo.
Here is a Victorian-era men's intaglio ring:
Photo Credit: Estate Liquidation.com
The intaglio process refers to other creations besides jewelry. You will find intaglio on decorative glass and sculpture with various materials. The term is also used in print-making, but that's not what we're talking about here. The glass plate below has been cut away to remove the blue color and add additional coloration:
Photo Credit: StyleandDesign.com
So there you go, another good word to know when you are out on the prowl for antiques and vintage treasures!