Cornflour is sometimes called Maize flour here - it's a very finely, finely ground form of cornmeal. I think you could grind cornmeal superfine in a coffeemill. I once needed very fine salt and I took regular table salt size granules and milled them into such a fine powder that I had to wear a dust mask cos I kept breathing the super fluffy salt. Over here Cornmeal is the same as Cornflour except that Cornflour is ground superfine. Be careful though - there is also something called Baking Cornflour / Maizena - that has added baking soda bicarbonate of soda added to id.
