The process of loosening, reducing, and dissolving the residue remaining in a pan after meat has been sautéed. After cooking, the meat is removed from the pan and a liquid such as wine, vinegar, stock, or juice is added to the remaining meat juices and bits, often sticking to the bottom of the pan. This flavorful residue is heated and combines with the liquid to produce a sauce or gravy for the meat. The longer the liquid is cooked, the thicker the mixture gets as the liquid evaporates and reduces. Cream or butter is often added to create a smoother sauce.
Although this is not the same as reducing, it is similar. When reducing, the liquid contents are rapidly boiled in order to reduce the volume of liquid so that the remaining contents are thicker and more flavorful. Deglazing involves less reduction and a slower cooking of the contents.