In a chemistry laboratory, a retort is a glassware device used for distillation or dry distillation of substances. It consists of a spherical vessel with a long downward-pointing neck. The liquid to be distilled is placed in the vessel and heated. The neck acts as a condenser, allowing the vapors to condense and flow along the neck to a collection vessel placed underneath.
In the chemical industry, a retort is an airtight vessel in which substances are heated for a chemical reaction producing gaseous products to be collected in a collection vessel or for further processing. Such industrial-scale retorts are used in shale oil extraction and the production of charcoal. A process of heating oil shale to produce shale oil, oil shale gas, and spent shale is commonly called retorting. Airtight vessels to apply pressure as well as heat are called autoclaves.
In the food industry, pressure cookers are often referred to as retorts, meaning "canning retorts", for sterilization under high temperature (116–130 °C).