Quick Answer: Flour is a powder used to make many different foods, including baked goods, as well as thickening dishes. It is made by grinding grains, beans, nuts, seeds, roots, or vegetables using a mill. Cereal flour, particularly wheat flour, is the main ingredient of bread, which is a staple food for many cultures. Archaeologists have found evidence of humans making cereal flour over 32,000 years ago. Other cereal flours include corn flour, which has been important in Mesoamerican cuisine since ancient times and remains a staple in the Americas, while rye flour is a constituent of bread in both Central Europe and Northern Europe. Cereal flour consists either of the endosperm, germ, and bran together, known as whole-grain flour, or of the endosperm alone, which is known as refined flour. 'Meal' is technically differentiable from flour as having slightly coarser particle size, known as degree of comminution. However, the word 'meal' is synonymous with 'flour' in some parts of the world.