Corn meal and corn flour are both derived from corn. In fact, their preparation involves the same ingredients and process. The only difference in how they are made is that corn meal is corn ground to a coarse or medium grind, and corn flour is ground to a fine consistency. This may seem like a small difference, but the two ingredients have very different uses.
Uses of corn meal
Corn meal is a staple food in many cultures. It is used to make many familiar foods, such as cornbread, polenta and corn muffins, and is used sometimes in cakes. Corn meal is also used to make breading for such dishes as fried fish.
Uses of corn flour
Much finer than corn meal, corn flour is used differently. It is ground to a powdery consistency. Not a food in itself, it is used for thickening soups and sauces. It can have a distinctive sweetcorn taste, and so might not be a good choice to use in more delicately flavoured dishes. It also can be used in biscuits and cakes.
Corn flour is white, while corn meal can be differently coloured, depending on what type of corn was used. Corn meal can be white, yellow or even blue.
Cornstarch, which is different from corn flour or corn meal, is known as corn flour in the United Kingdom. The two are not interchangeable, and care should be taken to not confuse them.
Corn meal that has a very coarse grind is sometimes known as corn grits.