Glossary of automotive design

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A glossary of terms relating to automotive design.


Some terms may be found at car classification.


One-box form
A categorization based on overall form design using rough rectangle volumes. In the case of the one-box, also called a monospace or monovolume, [1] it is a single continuous volume. Slight wedge formed front or rear are still generally placed in this category. E.g. buses and the original Ford Econoline. The equivalent French term is volume, which will sometimes be used by the British: "1-volume form".
Two-box form
A categorization based on overall form design using rough rectangle volumes. In the case of the two-box form, there is usually a "box" representing a separate volume from the a-pillar forward and second box making up the rest. E.g., Station wagon, shooting-brake, Scion xB (2006). The equivalent French term is volume, which will sometimes be used by the British: "2-volume form".
Three-box form
A categorization based on overall form design using rough rectangle volumes. In the case of the three-box form, there is a "box" delineating a separate volume from the a-pillar forward, a second box comprising the passenger volume, and third box comprising the trunk area—e.g., a Sedan. The equivalent French term is volume, which will sometimes be used by the British: "3-volume form".


The line running over the car, from headlight to taillight, tracing the car's silhouette.


Rear glass panel.
A demarcation or crease between a vehicles body panels and the side windows. Typically it refers to where an individual wears a belt attached to trousers.
Batsman's crease
A tangent break feature line running along the centreline of a car. This kind of feature can be seen on many modern Vauxhall, Opel and Chrysler models. Literally derived from the break found on the rear side of a cricket bat.
The trim or bodywork that surrounds a light, holds the face of an instrument in position, or decoratively conceals gaps between bodywork and components as an escutcheon. Often chrome or plastic
The housing for the instrument cluster on top of or as part of the dashboard.
The hood of the vehicle.
The trunk or liftgate of the vehicle.
Anything reflective added to a car to enhance appearance. May also be called chrome.
Body in White. Base chassis before customisation.
Butterfly doors
A type of door sometimes seen on high-performance cars. They are similar to scissor doors. While scissor doors move straight up via hinge points at the bottom of the A-pillar, butterfly doors move up and out via hinges along the A-pillar
Bustle back
First seen on the second generation Cadillac Seville, this was a short lived design trend. Inspired by the English coachbuilder Hooper & Co.'s "Empress Line" designs from the early 1950s, these were a unique take on trunk-body integration allowing for a shortened trunk and a rakish rear end.


Short for cabin. The enclosed compartment of a vehicle which contains the driver and passengers.
Cab back
The cab of the vehicle is moved to the rear of the vehicle. Cars such as a 1970s Corvette could be considered cab back design.
Cab forward
The cab of the vehicle is pushed forward. This design aesthetic was popular with Chrysler in the 1990s with the introduction of their LH platform cars.
Bodywork of a vehicle. Also the workshop at which automotive body work is built on a prototype or low volume production basis, typically with extensive handwork.
Character line
A line creased into the side of a car to give it visual interest. (interchangeable with swage line) Sometimes implemented by a rubbing strip.
Brightwork using chrome plating.
Material (usually plastic) added to exterior of the car which isn't structurally necessary. May be functional to keep out dirt/debris as in underbody cladding, or may be cosmetic.
Control panel
Generally used in a car or truck for heating and cooling inside car environment according to the passenger requirements. Basically it is divided into different modes, blower speed functions, AC, temperature, and fresh recirculation of air. Worldwide control panel manufacturers are BHTC, Delphi, Visteon, Valeo, etc.
The base of the windshield.


Dagmar bumpers
A slang term for chrome conical shaped styling elements which began to appear on the front bumper/grille assemblies of certain American automobiles following World War II. The term is derived from the notable physical attributes of Dagmar, a buxom early 1950s television personality known for low-cut gowns and pronouncedly conical bra cups.
Daylight Opening (DLO)
US DOT Term: For openings on the side of the vehicle, other than a door opening, the locus of all points where a horizontal line, perpendicular to the vehicle longitudinal centerline, is tangent to the periphery of the opening.
US DOT Term: For openings on the front and rear of the vehicle, other than a door opening, daylight opening means the locus of all points where a horizontal line, parallel to the vehicle longitudinal centerline is tangent to the periphery of the opening.
Daytime Running Lamp (DRL)
A daytime running lamp (DRL, also daytime running light) is an automotive lighting and bicycle lighting device on the front of a roadgoing motor vehicle or bicycle,[1] automatically switched on when the vehicle is in drive, emitting white, yellow, or amber light. Their job isn't to help the driver see the road but to help other road users see the vehicle.
Dash-to-Axle (ratio)
The critical relationship between front wheel centers and the windshield base. The most notable differences can be seen between cars with front-engine, front-wheel drive layout and front mid-engine, rear-wheel drive layout: the former tend to have longer front overhangs with a smaller dash-to-axle ratios, while the latter have shorter front overhangs with much greater dash-to-axle. Most so called premium vehicles (equipped with rear wheel drive) feature a relatively long dash-to-axle ratio.
The horizontal surface at the rear of the car, which usually serves as the trunk lid.
Dog leg
The area behind the rear door on a four-door car. This area is part of the quarter panel just behind the door and in front of the rear wheel house.
Down the Road Graphics (DRG)
The styling of the front end of the car, which people will instantly recognize and associate with a manufacturer. For example, the grille, lights and sometimes the DLO.
A convertible.


An external structure added to increase streamlining, deflect wind, and reduce drag.
The body-skin panel at the front of the car.
A car body style whose roofline slopes continuously down at the back found on cars with a single convex curve from the top to the rear bumper.
Fender (wings, UK)
Term for cowl covering the wheels of the vehicles. In more modern automobiles, this refers generally to the body panel or panels starting at the front "bumper" to the first door line excluding the engine hood. The opposite of the fender is the "quarter panel".
A design used in older (pre-unibody) cars, trucks, and SUVs. The power train and body are mounted to a rigid structural framework called a rail.


A vent on the side of the fender that can be used as hot-air outlet, but usually decorative.
The glassed-in upper section of the car's body. Daylight Opening (DLO) in turn describes the actual window areas only.
Gull-wing door
Car doors that are hinged at the roof rather than the side, as pioneered by the 1952 Mercedes-Benz 300SL race car. Opening upwards, the doors evoke the image of a seagull's wings.


A coupe or sedan lacking a center window post between the front windshield post and the rearmost window post or body section.
(1) The structural roof beam above the windshield. (2) The section of exhaust piping attached to the cylinder head.
Hofmeister kink
BMW's trademark reverse-sweep kick at the bottom of last roof pillar.
H-point (or HP (Hip Point))
The pivot point between the torso and upper leg portions of the body, either relative to the floor of the vehicle[1] or relative to the height above pavement level, as used in vehicle design.
Hood (Bonnet in English speaking countries outside North America with the exception of the Canadian Maritimes)
The engine cover on vehicles when the engine is located forward or aft of the passenger compartment.
Heater, ventilation and air condition. A major package constraint both technically as well in interior design.


Instrument Panel. The dashboard is termed the instrument panel in the automotive industry. Sometimes this term is confused with the instrument cluster, the group of speedometer, odometer and similar devices generally behind the steering wheel.


A car body style that calls for a body with smooth contours that continues to a tail that is abruptly cut.


Plastic clips onto the base of the windscreen under the bonnet to protect from leaves and flowers.
Leafscreen retainer
Bonded to the base of the windscreen to provide a mounting surface for the leafscreen


NACA duct
A distinctively shaped inlet that is flush and begins with a narrow, shallow inset and becomes progressively wider and deeper. The duct was developed to introduce cooling air into aircraft engine nacelles, while increasing the drag of the nacelle only minimally. The duct was developed at the National Advisory Committee for Aeronautics (NACA).


The distance the car's body extends beyond the wheelbase at the front (front overhang) and rear (rear overhang). In car style design terms, this is the amount of body that is beyond the wheels or wheel arches.
Obscuration band
Black graphite printed onto the glass to hide unsightly areas and improve aesthetics.


An open vehicle, usually with 4 doors, with a removable and/or retractable cloth top and a windshield characterized by the lack of integrated glass side windows. Contemporary uses of this name do not always follow this original description or apply to an open vehicle.
A structural member that connects the roof to the body of the car. Pillars are usually notated from front to back alphabetically (e.g. the A-pillar joins the windshield to the frontmost side windows, the B-pillar is next to the front occupants' heads, etc.).
US DOT Term: Means any structure, excluding glazing and the vertical portion of door window frames, but including accompanying molding, attached components such as safety belt anchorages and coat hooks, that (1) supports either a roof or any other structure (such as a roll-bar) above the driver's head or (2) is located along a side edge of a window.
The area at the base of the windshield where the wipers are parked. Also refers to the main chamber in an intake manifold.
Ponton styling
A 1930s–1960s design genre when distinct running boards and fully articulated fenders became less common and bodywork began to enclose the full width and uninterrupted length of a car in a markedly bulbous, slab-sided fashion.
Plug-in hybrid electric vehicle
A hybrid vehicle that can be plugged into the electric grid to recharge its battery to reduce gasoline usage. [2]
All the components that generate power and deliver it to the tyres.


(or rear quarter panel) refers to the panel at the back sides starting at the rear edge of the rearmost doors, bordered by at top by the trunk (boot) lid and at bottom by the rear wheel arches ending at the rear bumper. This is the opposite of the fender.
  • Literally, the term originally referred to the rear quarter or the car's length.


The first application of the term rake in vehicles was probably the tilting back of the windshield's top.[ citation needed ] Nowadays rake refers to the angle between the overall vehicle and the horizontal axis of the ground. If the back is higher than the front, the vehicle is said to have positive rake; if the front is higher than the back, this is negative rake. In early hot rod and custom cars, positive rake was created by varying tire size, and/or by suspension modification. In today's body design, positive rake is integral in some vehicles' styling, e.g. Mercedes E350 sedan, circa 2012/13.
An open vehicle, usually with 2 doors, with a removable and/or retractable cloth top and a windshield characterized by the lack of integrated glass side windows. Contemporary uses of this name do not always follow this original description. A classical roadster is a two-seater with a long hood and a short back, which means the driver is sitting in the rear of the vehicle (close to the rear axle). Usually it is a rear-wheel-driven car.
The body section below the base of the door openings sometimes called the "rocker panels", or "sills".
Rocker rail
Body armor protecting the Rocker, found mostly in off-road vehicles. Term coined by engineers at MetalCloak.[ citation needed ]
Rubbing strip
Plastic/rubber line or moulding to prevent side-swiping along the doors.


Saab hockey stick
The hockey stick is an automotive design feature seen on nearly all Saab automobiles. It is a C-pillar curve from the base of the rear passenger window that resembles the shape of an ice hockey stick or the Nike swoosh symbol.
Scissor doors
(Lamborghini doors) are automobile doors that rotate vertically at a fixed hinge at the front of the door, rather than outward as with a conventional door.
Inset or protrusion that implies the intake of air. May be functional for cooling/ventilation or purely ornamental. Also Shaker scoop.
Scowling headlamps
Headlamps styled along a V-shape as viewed from the front, giving the impression of a scowl.
The part of the body on a convertible or roadster where the windscreen is mounted. The term is used primarily in the UK.
Once a vehicle designed to carry hunters and sportsmen; now a station wagon or vehicle combining features of a station wagon and a coupe.
Shoulder line
The line or "shoulder" formed by the meeting of top and side surfaces extending from hood/fender shoulder to boot-lid/quarter-panel shoulder. The strongest example of this feature can be found on more modern of Volvo Cars.
The body section below the base of the door openings sometimes called the "rocker panels", or "rockers".
Sill line
Imaginary line drawn following the bottom edge of the greenhouse glass.
Six line
A line extending from the C-pillar down and around the rear wheel well.
Also called quarter glass; fixed glass located in between the side-door and boot.
A convertible top which is made out of flexible materials like PVC or textile.
Side covers for wheel arches, hiding the wheel—usually rear only. Also called fender skirts.
A raised lip or wing which is used to "spoil" unfavorable air movement across the body. Some designs are more functional than others.
Staggered wheel fitment
The front and rear wheels are different widths. On sporty rear-wheel-drive cars, the rear tires are usually wider than the front.
Crease in the sheet metal intended as a "speed line" styling feature. Exemplified in the doors of the Ferrari Testarossa.
Suicide door
Hinged doors, opening from the front of the car. If accidentally opened while driving at a high speed, such doors would be blown backward.
Swage line
Crease or curvature in the side of the body used to create visual distinction. Sometimes the crease is functional and improves rigidity of the outer body (interchangeable with character line).
Swedish kiss
A negative flick-out to a flat surface which frames trim sections or venting.


The distance across the car between the base of the left and right wheels (like wheelbase, but side-to-side).
A typically large vehicle built using frame-on-rail construction consisting of a cab and a separate bed for cargo.
(Bootin UK) Compartment for storage of cargo which is separate from the cab.
Tube Fender
Replacement fenders found on off-road vehicles designed as part of body armor for off-road vehicles. Used to protect the thin sheet metal bodies from damage while off-roading.
Generally refers to the way the sides of a car rounds inward toward the roof, specifically of the greenhouse above the beltline. This term is borrowed from nautical description of naval vessels.
Turn under
The shape of the rocker panel as it curves inward at the lower edge.


Shape of the car as seen in the side profile. May be positive, negative or neutral. If the front is lower than the rear, then it is wedge-positive. If the rear is lower it is wedge-negative. If the car appears level from front to rear, then it is wedge neutral.
Wheel arch
The visible opening in the side of a car allowing access to the wheel.
Wheel arch gap
The space between the tire and the wheel well. Currently there is a trend towards smaller wheel arch gaps. Sometimes referred to as Dead Cat Space due to the fact that, in winter, many domestic cats try to seek shelter in wheel wells of recently parked cars in an attempt to stay warm.
The distance front to back measured from where the front and rear wheels meet the ground.
Wheel well (also wheelhouse, wheelhousing, or bucket)
The enclosure or space for the wheel.
Windshield trim
US DOT Term: Molding of any material between the windshield glazing and the exterior roof surface, including material that covers a part of either the windshield glazing or exterior roof surface.
See Fender.

See also

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Cadillac Eldorado American personal luxury car

The Cadillac Eldorado is a luxury car manufactured and marketed by Cadillac from 1952 to 2002 over twelve generations.

Buick Electra

The Buick Electra is a full-size luxury car manufactured and marketed by Buick from 1959 to 1990 over six generations — having been named after heiress and sculptor Electra Waggoner Biggs by her brother-in-law Harlow H. Curtice, former president of Buick and later president of General Motors. The Electra was offered in coupe, convertible, sedan, and station wagon body styles over the course of its production — with rear-wheel drive (1959-1984) or front-wheel drive. For its entire production run, it utilized some form of GM's C platform. The Electra was superseded by the Buick Park Avenue in 1991.

Oldsmobile 98

The Oldsmobile 98 is the full-size flagship model of Oldsmobile that was produced from 1940 until 1996. The name — reflecting a "Series 90" fitted with an 8-cylinder engine — first appeared in 1941 and was used again after American consumer automobile production resumed post-World War II. It was, as it would remain, the division's top-of-the-line model, with lesser Oldsmobiles having lower numbers such as the A-body 66 and 68, and the B-body 76 and 78. The Series 60 was retired in 1949, the same year the Oldsmobile 78 was replaced by the 88. The Oldsmobile 76 was retired after 1950. This left the two remaining number-names to carry on into the 1990s as the bread and butter of the full-size Oldsmobile lineup until the Eighty Eight-based Regency replaced the 98 in 1997.

Car body styles are variable.

Ford Tempo

The Ford Tempo and its twin, the Mercury Topaz, are compact cars that were produced by the Ford Motor Company for model years 1984 to 1994. They were downsized successors to the boxy Ford Fairmont and Mercury Zephyr twins. The Tempo and Topaz were part of a rejuvenation plan by Ford to offer more environmentally friendly, fuel efficient, and more modern styled models to compete with the European and Japanese imports. While the car sold well, its innovation and aerodynamic design paved the way for the even more groundbreaking Ford Taurus. The Tempo and Topaz were replaced for 1995 by the "world car" platform sold in North America as the Ford Contour and Mercury Mystique.

Cadillac Calais

The Cadillac Calais was the entry-level Cadillac model that was sold from 1965 to 1976. Cadillac renamed its low-priced Series 62 in 1965 as the "Calais", after the French port city of Calais that overlooks the narrowest point in the English Channel. In Greek mythology, Calais was one of two winged sons of Boreas, god of the North Wind, and Oreithyea. With the exception of no convertible model, the Calais shared the same styling and mechanics as the better-equipped, more expensive Cadillac de Ville.

Buick Roadmaster Automobile

The Buick Roadmaster is an automobile that was built by Buick from 1936 to 1958, and again from 1991 to 1996. Roadmasters produced between 1936 and 1958 were built on Buick's longest non-limousine wheelbase and shared their basic structure with entry-level Cadillac and, after 1940, senior Oldsmobiles. Between 1946 and 1957 the Roadmaster served as Buick's flagship.

Cadillac Sixty Special

The Cadillac Sixty Special is a name used by Cadillac to denote a special model since the 1938 Harley Earl–Bill Mitchell–designed extended wheelbase derivative of the Series 60, often referred to as the Fleetwood Sixty Special. The Sixty Special designation was reserved for some of Cadillac's most luxurious vehicles. It was offered as a four-door sedan and briefly as a four-door hardtop. This exclusivity was reflected in the introduction of the exclusive Fleetwood Sixty Special Brougham d'Elegance in 1973 and the Fleetwood Sixty Special Brougham Talisman in 1974, and it was offered as one trim package below the Series 70 limousine. The Sixty Special name was temporarily retired in 1976 but returned again in 1987 and continued through 1993.

Cadillac Series 70

The Cadillac Series 70 is a full-size V8-powered series of cars that were produced by Cadillac from the 1930s to the 1980s. It replaced the 1935 355E as the company's mainstream car just as the much less expensive Series 60 was introduced. The Series 72 and 67 were similar to the Series 75 but the 72 and 67 were produced on a slightly shorter and longer wheelbase respectively. The Series 72 was only produced in 1940 and the Series 67 was only produced in 1941 and 1942. For much of the postwar era, it was the top-of-the-line Cadillac, and was Cadillac's factory-built limousine offering.

Cadillac Series 62

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Cadillac Series 61

The Cadillac Series 61 replaced the Series 60/65 in Cadillac's 1939 model range. It in turn was replaced by the Series 62 in 1940 only to return to production in model year 1941. Apart from model years 1943–1945 It remained in production through 1951.

Custom car Passenger vehicle that has been substantially altered in its appearance

A custom car is a passenger vehicle that has been either substantially altered to improve its performance, often by altering or replacing the engine and transmission; made into a personal "styling" statement, using paint work and aftermarket accessories to make the car look unlike any car as delivered from the factory; or some combination of both. A desire among some automotive enthusiasts in the United States is to push "styling and performance a step beyond the showroom floor - to truly craft an automobile of one's own." A custom car in British according to Collins English Dictionary is built to the buyer's own specifications.

Pillar (car)

Pillars are the vertical or near vertical supports of a car's window area or greenhouse—designated respectively as the A, B, C or D-pillar, moving from front to rear, in profile view.

Fender (vehicle)

Fender is the American English term for the part of an automobile, motorcycle or other vehicle body that frames a wheel well. Its primary purpose is to prevent sand, mud, rocks, liquids, and other road spray from being thrown into the air by the rotating tire. Fenders are typically rigid and can be damaged by contact with the road surface.

AMC Cavalier Concept car designed by American Motors Corporation

The AMC Cavalier was a concept compact car made by American Motors (AMC) in 1965. It was innovative by its symmetrical design and use of interchangeable body parts.

The following outline is provided as an overview of and topical guide to automobiles:

Buick Super

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Cadillac Series 355

The Cadillac Series 355 was manufactured by Cadillac from 1931 to 1935. They were 8-cylinder cars, sold in several models: a 2-door club coupe, a 2-door convertible, 4-door convertible, a 4-door sedan a 4-door town car and a 4-door limousine.

Cadillac de Ville series Car model

The Cadillac DeVille was originally a trim level and later a separate model produced by Cadillac. The first car to bear the name was the 1949 Coupe de Ville, a pillarless two-door hardtop body style with a prestige trim level above that of the Series 62 luxury coupe. The last model to be formally known as a DeVille was the 2005 Cadillac DeVille, a full-size sedan, the largest car in the Cadillac model range at the time. The next year, the DeVille was officially renamed the Cadillac DTS.

The VAM Lerma is an automobile that was designed and manufactured by Vehiculos Automotores Mexicanos from 1981 to 1983. The Lerma shared parts with other vehicles by VAM's license partner American Motors (AMC) to cut down manufacturing costs. It was VAM's top-of-the-line flagship model, which the company did not have since the discontinuation of the Classic (Matador) line in 1976. The VAM Lerma was unusual in offering a hatchback design focused at the top-end luxury market. The model was an indirect replacement of the VAM Classic and to some extent the VAM Pacer lines.


  1. "Car Design Glossary - Part 2: One-Box (Monospace or Monovolume)". Car Design News.
  2. See also "Hybrid Vehicles Gain Traction"