Cornmeal
Ground dried corn, fine to coarse depending on the grind, with a sweetish grain flavour.
Coarse cornmeal is sold as polenta or corn grits in most supermarkets, while fine cornmeal is easier to find in health food shops or Turkish and Eastern European grocers. Do not confuse it with cornstarch, which British English often calls cornflour and which is only a thickener.
Substitute:
Fine polenta works, or can be ground finer in a blender; the texture turns out slightly grainier, but the flavour stays the same.