Q. What is icing sugar?
A.
Having already gone to great lengths to prepare the definitive online British/American Dictionary of Flour Names, must we now do the same for sugar? Oh, the toil. Oh, the responsibility. Oh, the labor/labour!
Granulated sugar
= granulated sugar, white sugar
Castor sugar = superfine granulated sugar
Caster sugar = superfine granulated sugar
Icing sugar = confectioners' sugar, powdered sugar, 10X sugar, 4X sugar
Sugar crystals, crystal sugar = decorating sugar, coarse sugar
Rainbow sugar crystals = colored sugar
Most of this information exists elsewhere at Ochef.com, but it is useful finally to have it all in one place.