More about caster sugar than you need

Caster sugar is fine grain sugar kind of midway between ordinary (granulated)
sugar and icing (confectioner's) sugar. Its main advantage is that being fine
grained it absorbs/dissolves quicker, although in most cases you can use normal
sugar and get the same result. It gets its name from a sugar caster, which is
quite like a flour sifter, which is used to cast (sprinkle) the fine sugar over
the dish to be sweetened.
File under "Information you might never need" :-}