Sous-vide (/suːˈviːd/; French for “under vacuum”)[1] is a method of cooking in which food is placed in a plastic pouch or a glass jar and then placed in a water bath or steam environment for longer than normal cooking times (usually 1 to 7 hours, up to 48 or more in some cases) at an accurately regulated temperature. The temperature is much lower than normally used for cooking, typically around 55 to 60 °C (131 to 140 °F) for meat, higher for vegetables. The intent is to cook the item evenly, ensuring that the inside is properly cooked without overcooking the outside, and to retain moisture.

Source: Wikipedia