Formula racing is any of several forms of open-wheeled single-seater motorsport. The origin of the term lies in the nomenclature that was adopted by the FIAfor all of its post-World War II single-seater regulations, or formulae. The best known of these formulae are Formula One, Two, Three and Four. Common usage of "formula racing" encompasses other single-seater series, including the GP2 Series, which replaced Formula 3000 (which had itself been the effective replacement for Formula Two).
Categories such as Formula Three and GP2 are described as feeder formulae, which refers to their position below Formula One on the career ladder of single-seater motor racing. There are two primary forms of racing formula: the open formula that allows a choice of chassis and/or engines; and the control or "spec" formula that relies on a single supplier for chassis and engines. Formula Three is an example of an open formula, while Formula BMW is a control formula. There are also some exceptions on these two forms like Formula Ford where there is an open chassis formula but a restricted single brand engine formula.