Icing sugar is a fine, powdered form of white sugar. Its texture is ideal for making icing and buttercreams as it dissolves quickly and easily and does not really require the application of heat. Icing sugar is refined sugar in the form of a powder. Icing sugar is also known as confectionerâ??s sugar or powdered sugar. Its primary use as the name implies is icing or frosting. It is also used for sprinkling on baked goods and deserts. The white powder on a powdered donut is icing sugar. Some varieties of wedding cookies are rolled in powdered sugar. It is also the preferred sugar for things like whipped cream.