(1) A generic term used to denote a heat treatment wherein ithe microstructure and , consequently, the properties of a material are altered. "Annealing" frequently refers to a heat treatment wherby a previously cold-worked metal is softened by allowing it to recrystallize.
(2) The process of reducing the stresses in a material by the application of heat in a controlled manner. It involves glass or metal being heated and / or cooled slowly in a lehr (an oven or kiln), thus bringing about a relaxing of the internal stresses in the material.