2013 Mercedes-Benz CLS
The examples and perspective in this article deal primarily with the United States and do not represent a worldwide view of the subject. (February 2021)
A sedan or saloon ( British English)   is a passenger car in a three-box configuration with separate compartments for an engine, passengers, and cargo.  The first recorded use of sedan in reference to an automobile body occurred in 1912.  The name derives from the 17th-century litter known as a sedan chair, a one-person enclosed box with windows and carried by porters. Variations of the sedan style include the close-coupled sedan, club sedan, convertible sedan, fastback sedan, hardtop sedan, notchback sedan, and sedanet/sedanette.
A sedan ( /sɪˈdæn/) is a car with a closed body (i.e. a fixed metal roof) with the engine, passengers, and cargo in separate compartments.  This broad definition does not differentiate sedans from various other car body styles, but in practice, the typical characteristics of sedans are:
It is sometimes suggested that sedans must have four doors (to provide a simple distinction between sedans and two-door coupés); others state that a sedan can have four or two doors. : 134   While the sloping rear roofline defined the coupe, the design element has become common on many body styles with manufacturers increasingly "cross-pollinating" the style so that terms such as sedan and coupé have been loosely interpreted as "'four-door coupes' - an inherent contradiction in terms."  
When a manufacturer produces two-door sedan and four-door sedan versions of the same model, the shape and position of the greenhouse on both versions may be identical, with only the B-pillar positioned further back to accommodate the longer doors on the two-door versions. 
A sedan chair, a sophisticated litter, was an enclosed box with windows used to transport one seated person. Porters at the front and rear carried the chair with horizontal poles.  Litters date back to long before ancient Egypt, India, and China. Sedan chairs were developed in the 1630s. Etymologists suggest the name of the chair very probably came through varieties of Italian from the Latin sedere, meaning "to sit". 
The first recorded use of sedan for an automobile body occurred in 1912 when the Studebaker Four and Studebaker Six models were marketed as sedans.   There were fully enclosed automobile bodies before 1912. Long before that time, the same fully enclosed but horse-drawn carriages were known as a brougham in the United Kingdom, berline in France, and berlina in Italy; the latter two have become the terms for sedans in these countries. It is sometimes stated that the 1899 Renault Voiturette Type B (a 2-seat car with an extra external seat for a footman/mechanic) was the first sedan, since it is the first known car to be produced with a roof. A one-off instance of a similar coachwork is also known in a 1900 De Dion-Bouton Type D.  
A sedan is typically considered to be a fixed-roof car with at least four seats.  Based on this definition, the earliest sedan was the 1911 Speedwell, which was manufactured in the United States. : 87
In American English, Latin American Spanish, and Brazilian Portuguese, the term sedan is used (accented as sedán in Spanish).  In British English, a car of this configuration is called a saloon ( /səˈlun/). Hatchback sedans are known simply as hatchbacks (not hatchback saloons); long-wheelbase luxury saloons with a division between the driver and passengers are limousines. An equivalent term for sports sedan in the United Kingdom is super saloon. 
In Australia and New Zealand, sedan is now predominantly used, they were previously simply cars. In the 21st century, saloon is still found in the long-established names of particular motor races.[ citation needed] In other languages, sedans are known as berline ( French), berlina ( European Spanish, European Portuguese, Romanian, and Italian), though they may include hatchbacks. These names, like the sedan, all come from forms of passenger transport used before the advent of automobiles. In German, a sedan is called Limousine and a limousine is a Stretch-Limousine. 
In the United States, two-door sedan models were marketed as Tudor in the Ford Model A (1927–1931) series.  Automakers use different terms to differentiate their products and for Ford's sedan body styles "the tudor (2-door) and fordor (4-door) were marketing terms designed to stick in the minds of the public."  Ford continued to use the Tudor name for 5-window coupes, 2-door convertibles, and roadsters since all had two doors.  The Tudor name was also used to describe the Škoda 1101/1102 introduced in 1946.  The name was popularized by the public for a two-door model and was then applied by the automaker to the entire line that included a four-door sedan and station wagon versions. 
In the United States, the notchback sedan distinguishes models with a horizontal trunk lid. The term is generally only referred to in marketing when it is necessary to distinguish between two sedan body styles (e.g. notchback and fastback) of the same model range.
Several sedans have a fastback profile, but have a hatchback-style tailgate which is hinged at the roof. Examples include the Peugeot 309, Škoda Octavia, Hyundai Elantra XD, Chevrolet Malibu Maxx, BMW 4 Series Grand Coupe, Audi A5 Sportback, and Tesla Model S. The names hatchback and sedan are often used to differentiate between body styles of the same model. To avoid confusion, the term hatchback sedan is not often used.
There have been many sedans with a fastback style.
Hardtop sedans were a popular body style in the United States from the 1950s to the 1970s. Hardtops are manufactured without a B-pillar leaving uninterrupted open space or, when closed, glass along the side of the car.    The top was intended to look like a convertible's top but it was fixed and made of hard material that did not fold. 
All manufacturers in the United States from the early 1950s into the 1970s provided at least a 2-door hardtop model in their range and a 4-door hardtop as well. The lack of side bracing demanded a particularly strong and heavy chassis frame to combat unavoidable flexing. The pillarless design was also available in four-door models using unibody construction.  For example, Chrysler moved to unibody designs for most of its models in 1960 and American Motors Corporation offered four-door sedans, as well a four-door station wagon from 1958 until 1960 in the Rambler and Ambassador series. 
In 1973, the US government passed Federal Motor Vehicle Safety Standard 216 creating a standard roof strength test to measure the integrity of roof structure in motor vehicles to come into effect some years later. Production of hardtop sedan body style ended with the 1978 Chrysler Newport. For a time roofs were covered with vinyl and B-pillars were minimized by using styling methods like matt black finishes. Stylists and engineers soon developed more subtle solutions. 
A close-coupled sedan is a body style produced in the United States during the 1920s and 1930s. Their two-box boxy styling made these sedans more like crossover vehicles than traditional three-box sedans. Like other close-coupled body styles, the rear seats are located further forward than a regular sedan. : 43  This reduced the length of the body; close-coupled sedans, also known as town sedans, were the shortest of the sedan models offered. 
Models of close-coupled sedans include the Chrysler Imperial,   Duesenberg Model A,  and Packard 745 
A two-door sedan for four or five passengers but with less room for passengers than a standard sedan. A Coach body has no external trunk for luggage. Haajanen says it can be difficult to tell the difference between a Club and a Brougham and a Coach body as if manufacturers were more concerned with marketing their product than adhering to strict body style definitions. 
Close-coupled saloons originated as four-door thoroughbred sporting horse-drawn carriages with little room for the feet of rear passengers. In automotive use, manufacturers in the United Kingdom used the term for the development of the chummy body where passengers were forced to be friendly because they were tightly packed. They provided weather protection for extra passengers in what would otherwise be a two-seater car. Two-door versions would be described in the United States and France as coach bodies.  A postwar example is the Rover 3 Litre Coupé.
Produced in the United States from the mid-1920s to the mid-1950s, the name club sedan was used for highly appointed models using the sedan chassis. : 44 Some people describe a club sedan as a two-door vehicle with a body style otherwise identical to the sedan models in the range.  Others describe a club sedan as having either two or four doors and a shorter roof and therefore less interior space than the other sedan models in the range. : 44
Club sedan originates from the club carriage (e.g. the lounge or parlour carriage) in a railroad train. : 44
From the 1910s to the 1950s, several United States manufacturers have named models either Sedanet or Sedanette. The term originated as a smaller version of the sedan;  however, it has also been used for convertibles and fastback coupes. Models that have been called Sedanet or Sedanette include the 1917 Dort Sedanet,  King,  1919 Lexington,  1930s Cadillac Fleetwood Sedanette,  1949 Cadillac Series 62 Sedanette,  1942-1951 Buick Super Sedanet,   and 1956 Studebaker.
The principal volumes of the traditional sedan can be split into separate compartments or boxes: the hood/bonnet is the first box; the passenger compartment the second, and the trunk/boot the third - i.e. it's a 'three-box' car.