A powdery flour made of finely ground cornmeal, NOT to be confused with cornstarch.
The exception is in British recipes where the term "cornflour" is used synonymously with the U.S. word cornstarch.
Corn flour is used for breading and in combination with other flours in baked goods. Corn flour is milled from the whole kernel, while cornstarch is obtained from the endosperm portion of the kernel.