The verb braiser (to braise) comes from the French noun (une) braise, which means ember. In ancient times, the cooking vessel was placed in hot embers, and additional hot embers were placed on top of the lid. The heat came from both top and bottom. Nowadays, oven or stove can be used.
Braising is cooking by wet heat with the food item partially immersed in liquid, at low temperature - a feu doux (literally soft fire) and is used for small cuts of meat (second and third categories).
Braising is considered as a mixte cooking since the item is firstly seared or sauteed (concentration) then moistened with stock (extraction). Famous receipes are "fricassee de volaille" (mixte a blanc since using a white stock) and "navarin d'agneau" (mixte a brun since using a brown stock).