Is the sugar yielded from sugar cubes considered a kind of sugar? If so, what is it called? Confectionery sugar?
I have never seen, heard of, or found any reference to powdered sugar cubes. Sugar cubes are made with white granulated sugar. They can also be colored or flavored, but the typical cubes found at the market are plain white sugar.
Powdered sugar is also known as confectioner's sugar and is used for frostings, dusting the tops of cakes & funnel cakes, etc. Powdered sugar can be made by blending or processing granulated sugar.