Searing is a technique used in grilling, roasting, braising, sauteeing, etc. that cookings the surface of the food (usually meat, poultry or fish) at high temperature so that a caramelized crust forms. A similar technique, browning, is typically used to sear or brown all sides of a particular piece of meat, fish, poultry, etc. before finishing it in the oven. Similar to searing, the goal is to retain the internal juices and flavors of the meat.
It is commonly believed that this acts to "lock in moisture" while cooking finishes, resulting in a juicier end product. However it has now been scientifically shown that searing results in a loss of moisture. Nonetheless it remains an essential technique in cooking meat as the contrast in taste and texture between the crust and the interior makes the food more interesting to the palate.
Typically in grilling, the food will be seared over very high heat and then moved to a lower temperature area of the grill. In braising, the seared surface acts to flavor, color and otherwise enrich the liquid in which the food is being cooked.
