A sedan car, American English terminology (saloon in British English), is one of the most common body styles of the modern automobile. At its most basic, the sedan is a passenger car with two rows of seats and adequate passenger space in the rear compartment for adult passengers. The vehicle most commonly has a separate trunk (boot in British English), for luggage at the rear. However, rear-engined sedans include models by Chevrolet, Tatra, and Volkswagen.
A sedan seats four or more people and has a fixed roof that is full-height up to the rear window. The roof structure will typically have a fixed "B" pillar on sedan models. Most commonly it is a four-door; two-door models are rare, but they do occur (more so historically). In the U.S., the term sedan has been used to denote a car with fixed window frames, as opposed to the hardtop style without a "B" pillar and where the sash, if any, winds down with the glass. However, true hardtops have become increasingly rare.
Marketing terminology is often misleading in this area - for example, Daimler AG calls the Mercedes-Benz CLS-Class sedan a four-door coupé because of its semi-fastback design tries to give the impression of a coupé. Certain sedans are edging close to being one-box vehicles, where the windshield is steeply raked from the hood and the rear window slopes toward almost the end of the car, leaving just a short rear deck that is part of the trunk lid - the 2006 4-door Honda Civic is an example of this. They are not fastbacks because their bodyline changes from the roof to the rear deck. Their steeply raked rear windows end with a decklid that does not continue down to the bumper. Instead, their rear ends are tall - sometimes in a Kammback style - to increase trunk space.
The Society of Automotive Engineers defines such a vehicle as any two-door model with rear accommodation greater than or equal to in volume (a calculation made by adding the legroom, shoulder room, and headroom). By this standard, the Chevrolet Monte Carlo, Ferrari 612 Scaglietti, and Mercedes-Benz CL-Class coupés are all two-door sedans. Only a few sources, however (including the magazine Car and Driver), use the two-door sedan label in this manner.
In the popular vernacular, a two-door sedan is defined by appearance and not by volume; vehicles with a B-pillar between the front and rear windows are generally called two-door sedans, while hardtops (without the pillar, and often incorporating a sloping backlight) are called coupés.
The Mazda RX-8 meets the volume requirement to be called a sedan, but it has vestigial rear-hinged rear doors, so some call it 2+2-door sedan. Another term for a coupé endowed with rear-hinged doors is a "quad coupé." Although this may simply be vernacular, based on a possible copyright by General Motors, for its Saturn Ion Quad-Coupe.
In historic terminology a sedan will have a frame around the door windows, while the hardtop has frameless door glass. A true hardtop sedan design also has no "B" pillar (the roof support behind the front doors). This body style has an open feel, but requires extra underbody strengthening for structural rigidity. The hardtop design can be considered separately (i.e., a vehicle can be simply called a four-door hardtop), or it can be called a hardtop sedan. During the 1960s and 1970s, hardtop sedans were often sold as sport sedans by American manufacturers and were among the top selling body styles. During the 1980s, automakers in the U.S. focused on removing weight and increasing strength, and their new four-door sedans with B-pillars were called pillared hardtops or pillared sedans. The sport sedan term has since been appropriated for other uses. In Japan, and among Japanese manufacturers worldwide, the hardtop design was popular among luxury sedans throughout the 1990s.
Hatchback (a.k.a. liftback) sedans typically have the fastback profile, but instead of a trunk lid, the entire back of the vehicle lifts up (using a liftgate or hatch). A vehicle with four passenger doors and a liftgate at the rear can be called a four-door hatchback, four-door hatchback sedan, or five-door sedan. An example of such is the Chevrolet Malibu Maxx. There can also be two-door hatchback sedans (three-door sedans), by the same technical explanation for two-door sedans. Examples of this design are the Volkswagen Golf, and Renault Vel Satis.
Chauffeured limousine sedans are primarily used by businesses for meetings as well as for airport transportation. Main vehicles used for these means are usually the Lincoln Town Car, a Cadillac, or a Mercedes. Chauffeurs are professional drivers, usually with experience in the transportation industry or tourism industry. Chauffeured sedans are owned either by private owners, livery services, or corporations. Large corporations as well as governments commonly provide luxury sedans to their top executives as well as VIP guests. Chauffeured sedans, such as the Lincoln Town Car, may also be stretched into limousines that are capable of seating up to twenty people. Another, smaller number of chauffeured sedans are owned by private individuals who hire chauffeurs to drive them in their own cars.
The derivation from the town of Sedan in France, where it was said to have been made or first used, lacks historical evidence, according to OED. The word sedan was later used to refer to a litter or windowed box containing a passenger seat carried by two or more bearers.
In British English the configuration is called a saloon and has its engine under the bonnet at the front, and a boot for luggage at the rear. The British English term is sometimes used by British car manufacturers in the United States. For example, the Rolls-Royce Park Ward was sold as a saloon in the United States, while the smaller Silver Seraph was called a sedan.
In Australia and New Zealand, the American term sedan is used, albeit with the British terms boot and bonnet being retained. In other languages, sedans are known as berline (French), berlina (Spanish, European Portuguese, Romanian, and Italian); although these terms also may include hatchbacks. These terms, besides sedan, derive from types of horse-drawn carriages. In German, the term Limousine is used for sedans, as well as for limousines.