What is the difference between cornstarch and flour?

To be blunt, the term corn flour has been rendered useless by its multiple and diverse meanings. In the UK, corn flour refers to the white, powdery corn derivative that we call cornstarch in the USA. In the USA, corn flour, depending on the source, can refer to very finely ground white or yellow corn meal, corn meal mix (often used in corn bread), or the semi-fine ground corn meal used in tortillas and other native American/Mexican dishes. Thus, consider the source and try to apply some common sense when using a recipe calling for non-specific corn flour.