Sweating in cooking is the gentle heating of coarsely cut vegetables in a little oil or butter, with frequent stirring and turning to ensure that any emitted liquid will evaporate. Sweating usually results in tender, sometimes translucent, pieces. Sweating is often a preliminary to further cooking in liquid; onions, in particular, are often sweated before including in a stew

Stew

A stew is a combination of solid food ingredients that have been cooked in liquid and served in the resultant gravy. Ingredients in a stew can include any combination of vegetables , meat, especially tougher meats suitable for slow-cooking, such as beef. Poultry, sausages, and seafood are also used...

. This differs from sautéing

Sautéing

Sautéing is a method of cooking food, that uses a small amount of fat in a shallow pan over relatively high heat. Ingredients are usually cut into pieces or thinly sliced to facilitate fast cooking. The primary mode of heat transfer during sautéing is conduction between the pan and the food being...

in that sweating is done over a much lower heat, sometimes with salt added to help draw moisture away, and making sure that little or no browning takes place.