If you've started to look at cake and frosting recipes you are probably realizing you need to learn a whole new vocabulary. It doesn't help that some ingredients are called different things by different people. Here's a quick guide to the different types and names of sugar you may encounter.
1) Granulated Sugar - If your recipe calls "sugar" and doesn't say anything else, this is what it means. It is regular table sugar and is refined from either sugar cane or beets.
2)Caster Sugar - Also called "superfine" sugar, baking sugar, and bar sugar. It is ground finer than granulated sugar and dissolves excellently in liquids. Commonly used in meringues and very light cakes where you do not want any grittiness from your sugar.
3)Icing Sugar - Also called confectionary sugar, and 10X sugar. Commonly used in icings and frostings as well as to dust and garnish baked items. Sift before use as this can clump when left out.
4)Unbleached - This is essentially granulated sugar that has been processed less and thus has a light blond color. You can use this anytime you would be using granulated sugar.
5)Sanding Sugar - Also called Crystal sugar. This sugar has larger crystals and is used for decorating baked items.
Brown sugars are a category in and of themselves and deserve their own post. Happy baking!