In oil, a plant, usually comprising distillation units and a variety of additional specialist units, for the manufacture of so-called refined products from crude oil. Major refined products include naphtha, gasoline, gasoil (heating oil), jet fuel, low sulfur and high sulfur fuel oil.

In copper and lead, a refinery is a plant which further purifies metal produced in a smelter. In zinc, it is a plant which produces purer metal than could be produced in a smelter. In aluminum, it denotes a plant which refines bauxite into alumina.