During World War II, Germany fielded many aircraft and rockets whose fuels, and oxidizers, were designated (letter)-Stoff.
In German, Stoff means roughly the same thing as English "stuff", both of which derive from the Old French word estoffe (meaning cloth or material). Stoff has as broad a range of meanings, ranging from "chemical substance" to "cloth", depending on the context. The common elements (hydrogen, oxygen, carbon and nitrogen) are named respectively Wasserstoff, Sauerstoff, Kohlenstoff and Stickstoff (literally: 'water-stuff', 'sour-stuff', 'coal-stuff' and 'smother-stuff', respectively) in German. Stoff was used in chemical code names in both World War I and World War II. Some code names were reused between the wars and had different meanings at different times; for example, T-Stoff meant a rocket propellant in World War II, but a tear gas (xylyl bromide) in World War I. The following list refers to the World War II aerospace meanings if not noted otherwise.