A muffle furnace is a piece of laboratory equipment used for high temperature applications. It has a closed chamber for controlled heating and cooling using gas or electric heat sources. The furnace is suitable for heating, annealing, and sintering in a controlled atmosphere. Some synonyms for a muffle furnace include high-temperature furnace, tempering furnace, annealing furnace, sintering furnace, and controlled atmosphere furnace. Each synonym highlights the different applications that the furnace can be used for, depending on the specific needs of the laboratory or industrial process. Nevertheless, all these furnaces operate at high temperatures and provide a controlled environment for heating materials.