( http://whatscookingamerica.net/Glossary/C.htm)
roux (roo) - Classical cookbooks written as far back as the mid-1500s state that roux is derived from the French word "rouge" meaning "red" or "reddish" in color. Thus, the origin of the name. A roux describes a mixture of equal amounts of fat (butter, meat drippings, or fat) and flour, which are cooked together at the very start of the recipe before any liquid is added. It is used as a basis for thickening sauces. A roux is the basis for many Louisiana dishes, particularly gumbo, but also etouffees, sauce piquantes, and more. Preparation of a roux is dependent on cooking time; the longer you cook, the darker the roux. Roux must be stirred constantly to avoid burning If you see black specks in your roux, you've burned it; throw it out and start over.
( http://whatscookingamerica.net/Glossary/C.htm)
