http://en.wikipedia.org/wiki/Cornmeal
Cornmeal is flour ground from dried corn, and is a common staple food. In the United States it is also called cornflour. (In the United Kingdom, the word cornflour denotes cornstarch.)
Steel ground yellow cornmeal, common mostly in the United States, has the husk and germ of the maize kernel almost completely removed. It is conserved almost indefinitely if stored in an airtight container in a cool, dry place.

Stone ground cornmeal retains some of the hull and germ, lending a little more flavor and nutrition to recipes. It is more perishable, but will store longer if refrigerated. However it too can have a fairly long shelf life of many months if kept in a reasonably cool place. It can also be used for cornmeal cakes.

http://en.wikipedia.org/wiki/Maize#Food
Corn and cornmeal (corn flour) constitutes a staple food in many regions of the world. Corn meal is made into a thick porridge in many cultures: from the polenta of Italy, the angu of Brazil, the mămăligă of Romania, to mush in the U.S. or the food called sadza, nshima, ugali, tuwan-masara and mealie pap in Africa. Corn meal is also used as a replacement for wheat flour, to make cornbread and other baked products. Masa (cornmeal treated with lime water) is the main ingredient for tortillas, atole and many other dishes of Mexican food.





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Note added at 42 minute (2009-02-28 15:41:54 GMT)
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"Corn flour", "maize flour"
Finely ground cornmeal, corn flour comes in yellow and white and 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. In British recipes the term "cornflour" is used synonymously with the U.S. Word cornstarch. masa harina is a special corn flour that's the basic ingredient for corn tortillas.
http://en.wikipedia.org/wiki/Corn_flour

Corn (maize) flour is popular in the Southern and Southwestern US, Mexico, South America, and Punjab regions of India and Pakistan. Coarse whole-grain corn flour is usually called corn meal. Corn meal that has been bleached with lye is called masa harina (see masa) and is used to make tortillas and tamales in Mexican cooking. Corn flour should never be confused with cornstarch, which is known as "cornflour" in British English. Cornstarch is just the "refined form" of Cornflour.
http://en.wikipedia.org/wiki/Flour