confectioner' sugar used for baking

•Confectioners' sugar is regular granulated white sugar that's pulverized to a powder so fine it's basically sugar dust. On its own, this powder will draw water from the air and clump, so cornstarch is added to prevent this (but don't worry, you won't taste it).

•Powdered sugar is used in industrial food production when a quick-dissolving sugar is required. Home cooks use it principally to make icing or frosting and other cake decorations. It is often dusted onto baked goods to add a subtle sweetness and delicate decoration.