The support structure for the roof of a vehicle. Usually located on either side of an automobile’s rear window for coupes and sedans, the location may vary based on the make and model.

Cabin Lighting

Lighting fixtures which are located in the headliner of a vehicle. These lights are used to illuminate the interior cabin space of an automobile both in the front and rear sections. Typically, lighting is comprised of either halogen bulbs or LEDs.

Caliper Configuration

A breakdown of the total number of hydraulic pistons which are used within a vehicle’s brake caliper as well as the overall arrangement of those pistons. This type of configuration has a specific effect on the braking system’s functionality and efficiency.

Caliper Type

The specific type of brake caliper used in a vehicle. There are three primary variations of calipers: sliding, dual-sliding, and monoblock.

Cap Reduction

Also known as capital reduction, this term refers to all the factors which may reduce the overall cost of a vehicle which is being leased (i.e. its “capitalized cost). Factors which may reduce the cost include a cash down payment, a trade-in, or a rebate offered by the dealership or manufacturer.

Capitalized Cost

Frequently referred to as the “cap cost,” the actual negotiated price of a vehicle which is being leased. This price is determined between the dealership/manufacturer and the lease holder. It is one of several factors which determines the overall monthly lease payment which must be paid. A “cap reduction” can reduce this cost and lower monthly payments.

Captive Finance Company

An automobile lending company which acts as a subsidiary operation to a vehicle manufacturer. These companies are used within a manufacturer’s operations as a means to provide direct financing options for their buyers. Their primary business is to provide financing options for the sales and leasing that are specific to the parent automotive manufacturing firm.

Carbon Dioxide

A gas which is naturally current in the environment and is released as a byproduct of combustion engines. Fossil fuels break down during combustion and produce this gas in the exhaust. Its molecular composition includes two oxygen atoms which are bonded to one single carbon atom. This gas remains a concern to environmentalists due to its “greenhouse gas” effect.

Carbon Footprint

A measurement which outlines a vehicle’s overall consumption of natural resources required to operate compared with the Earth’s capacity to produce and regenerate those resources. As more efficient vehicles come into consumer demand, the overall carbon footprint numbers have been reduced in a large number of automobile makes and models.

Carbon Monoxide

As a byproduct of an engine’s combustion of fossil fuels, this “greenhouse gas” is a component of the exhaust of most standard gasoline automobiles. Its molecular structure includes one single carbon and oxygen atom bonded together. This type of gas can be dangerous and potentially lethal to drivers if exposed to high enough levels in enclosed spaces.


Used in older combustion engine-based vehicles, this system provides fuel into the engine to power a car. It is mounted on an engine’s intake manifold and responds to driver engagement of the gas pedal to supply fuel to the engine. Newer models of vehicles replaced carburetors with fuel injection systems.

Cargo Area Features

A vehicle’s built-in features within a cargo area which are all included to provide specific benefits for occupants. Examples include enhanced storage capacity or removable seating.

Cargo Door Type

The door which is used for the cargo area of a vehicle. Examples of doors include horizontal split-hinge, vertical split-hinge, or a liftgate style.

Cargo Hauler

A vehicle which is specifically adept or designed to effectively haul cargo. Pickup trucks are an example of this type of vehicle.

Cargo Tie Down

Various mechanisms which are used to tie down cargo and secure it to the cargo storage area. Tie downs help to anchor cargo to a vehicle and prevent anything from falling out during transport Examples include hooks, straps, ropes, and eyelets.

Cash Rebates

Customer direct cash payouts provided by vehicle manufacturers at the time of purchase. Rebates are used to reduce the overall asking price, and they are one of several components which determine the overall final price a buyer pays for an automobile. Buyers can opt to use the rebate directly as part of a vehicle’s down payment or to receive a cash or credit payout for the amount to use at their discretion. In many cases, a rebate is a highly effective method to attract prospective buyers and convince them to agree to a vehicle purchase or lease.

Catalytic Converter

A canister which is present in a vehicle’s exhaust system and typically placed before the muffler. It contains a substance which chemically reacts with a vehicle’s exhaust to bond harmful elements to this component and remove them from the emissions. This process helps to reduce environmentally harmful pollutants and emissions from vehicles.

Catalytic Converter Heat Shield

Used in a catalytic converter, this shield provides a panel around the system to prevent the dissemination of heat outward to other areas around a vehicle’s exhaust. Heat shields are typically metallic and may include insulation to improve the overall heat containment within the catalytic converter.


Refer to “Crankcase Ventilation Filter” for more information.

Center Console Trim

The type of material used in a vehicle’s trim on the center console. This trim is included to supplement and enhance the overall aesthetic appearance of a vehicle’s internal layout. Primary examples of console trim include wood, leather, metal, and composite materials.

Center of Gravity

A physical property that reflects the point where an object’s mass begins to behave as though it was concentrated. Within a vehicle’s makeup, center of gravity helps to determine its rollover potential. A lower center of gravity indicates that a vehicle may be less likely to roll over after it has been destabilized or has been involved in an accident. Accordingly, vehicles with higher centers of gravity may be at greater risk of rollovers in aversive conditions. In most cases, vehicle purchasers prefer makes and models with lower centers of gravity and lower risk of rollover.

Certification Sales Region

A specific geographical region where particular vehicles are certified by the Environmental Protection Agency (EPA) for sale to the public. In most cases, this sales region is identified and distinguished by the particular states it encompasses. Many vehicle sales benefit from this distinction due to their improved environmental standards identified by the EPA.

Certified Pre-Owned Vehicle

A used vehicle from a franchised dealership which adheres to a series of standards and requirements for quality. Dealerships determine specific vehicle makes and models which must be put through a certification process for overall vehicle condition. By certifying pre-owned vehicles using these standards, manufacturers also include a warranty on the vehicle’s continued operation. Certification includes a thorough assessment of a vehicle’s condition including a full inspection and the completion of any requirement maintenance, service, and repairs.

Charcoal Canister

A device which is used to capture hydrocarbons present in vapors from raw fuel in the vehicle’s fuel tank or carburetor bowl before they can filter outward and escape into the air and atmosphere. This canister is another method used by vehicle manufacturers to reduce the total amount of pollutants a vehicle may release into the environment.

Child Seat

A seat equipped within a vehicle to safely transport small children who may not safely fit into typical seating. Using a harness to secure the child seat to the cabin, these installations are also designed to work effectively with a vehicle’s restraint (seatbelt) system.

Child Seat Anchors

Built into most vehicles, these attachment points are used to connect child safety seats using the seatbelts to stabilize and secure child seating. Anchors must be built to meet or exceed ISOFIX international safety standards for child seat connection. In the U.S. market, this standard is frequently referred to as the LATCH system, or “Lower Anchors and Tethers for Children” system.

Childproof Safety Features

A collection of all the various options a vehicle employs to make it safer for young children and to prevent any accidents. Common safety features include disabling vehicle windows, door locks to prevent opening, and the disabling of a passenger air bag which can prevent potential injury to children who are too small to endure its force.

Choke Linkage

Present within older vehicles equipped with a carbureted engine, this assembly includes all the parts which control the amount of cold air which can enter an engine prior to it reaching an optimal running temperature. Limiting the cold air intake ensures that the carburetor will vaporize fuel at properly efficient levels and prevent any engine performance problems associated with lower temperature thresholds.

City Fuel Economy

The amount of mileage a vehicle can typically expect to travel per gallon of fuel within a stop-and-go city-based environment. City-based economy figures are determined using EPA simulation amounts from laboratory tests with typical city driving requirements and conditions. Improved efficiency standards extend both to highway fuel consumption as well as city-based consumption. Many hybrid vehicles have increased in popularity by offering vastly superior city fuel economy levels compared with standard engines.

Climate Control

In-cab controlled heating and air conditioning systems enabled by an automated computer system and adjustable based on specific user settings. Occupants can adjust the specific settings, and the computer-controlled system will provide either the heating or cooling to reach that specific level.

Climate-Controlled Seat Filter

An air filter which is used to filter out contaminants from ventilation which provides air conditioning to vehicle seats.

Climate-Controlled Seats

Seats which are equipped with various mechanisms to control both their cooling and their heating.


The agent responsible for confirming a car purchase or leasing deal arrangement. Typically, a closer is an experienced salesperson or sales manager within a dealership. Using their skills and experience, these professionals work to successfully negotiate and close a sale. They are particularly adept at converting prospective, hesitant shoppers into buyers using a variety of negotiation tactics. These tactics may include added incentives, discounts, rebates, and other benefits to the buyer.

Clutch Bushing and Clutch Linkage

Mechanical parts within the clutch system which connect the clutch mechanism to the vehicle’s clutch pedal. These components are present only in non-hydraulic clutch systems. They are both required to ensure the proper shifting of gears when the clutch pedal is activated by a vehicle driver.

Clutch Fluid

The fluid used within a hydraulic-based manual or clutch transmission system. This fluid provides the method for a manual transmission to disengage the clutch from the vehicle’s flywheel. Problems with this fluid could negatively affect the overall performance of the clutch system.

Clutch Fork Ball Stud

A component housed in the manual transmission, this stud provides the pivot point for a clutch fork within the overall clutch housing of manual transmissions. The pivot point is essential to enable the clutch to actively engage and effectively shift gears within the transmission.

Clutch Lines and Clutch Hoses

Critical components which allow the clutch system in a hydraulic-based manual transmission to effectively function. Within a hydraulic-actuated clutch, these tubes are responsible for carrying and distributing fluid to the clutch master cylinder as well as the slave cylinder.

Clutch Master Cylinder

Within a manual transmission system using a clutch actuated hydraulically, this cylinder activates a slave cylinder. The process also actuates the clutch fork to disengage the clutch whenever it is manually depressed by the driver. The small-bore hydraulic cylinder ensures a proper shift between gears in manual transmissions by preventing the clutch from activating when it should not be functioning. It is an essential component to any hydraulically activated clutch as it enables the proper function within a transmission whenever a driver presses or depresses the clutch pedal.

Clutch Pedal

A pedal which is located on the floor of a vehicle and to the left of the brake pedal. When it is depressed, this mechanical system disengages the clutch from the flywheel to enable manual shifting between gears. It is the essential component to a manual transmission in most vehicles equipped with this type of system.

Collapsible Steering Column

A steering column which can collapse as necessary in the event of a collision or other accident. When a high force frontal impact occurs, this column will fall under pressure to significantly reduce the impact potential for a driver. It provides an added level of collision safety within an automobile.

Collision Insurance

Automobile insurance which specifically covers damage that has occurred due to a collision. Collisions include a range of potential objects such as another vehicle, a sidewalk or wall, an obstacle in the roadway, or any other potential object.

Combined Fuel Economy

A measurement which denotes the average miles a vehicle can travel on one gallon of fuel in a combined highway and city environment. The EPA performs independent testing of vehicles to determine the specific miles per gallon (MPG) rating for fuel economy. Within these tests, driving conditions for combined fuel ratings include 55% highway and 45% city-based conditions.


A display within a vehicle’s interior which indicates the specific direction a vehicle’s front end is facing and moving toward. This display can be either in analog or digital format depending on a vehicle’s particular features.

Comprehensive Insurance

An insurance level which includes coverage for damage beyond that which was caused by an object or another vehicle. This provides an added layer of insurance protection for an automobile.

Compression Ratio

The specific ratio between a vehicle’s engine cylinder volume while the piston is in the direct bottom-center and the cylinder volume when the piston is in the upper center. This measurement yields the total ratio between the maximum and minimum volume within the cylinder of an internal combustion engine.


A storage component in located in a vehicle’s front dash or headliner in the cabin. Specific locations of consoles will vary based on a vehicle’s year, make, and model. They are usually located between the front seats or underneath the seats.

Convertible Roof Type

Specific types of roofs installed on a convertible vehicle. These tops can vary extensively based on a vehicle’s make or model. Examples include hard tops, soft tops, T-tops, and Targa tops. Roofs can be either manually or power operated depending on the particular vehicle.

Convertible Wind Blocker

Otherwise known as an “aeroboard,” a plastic or glass shield installed on a convertible which helps to prevent fast-moving air from reversing into the cabin as it moves over the low pressure, lower velocity air present in the passenger compartment. Without this installation, the air displacement would significantly impact all passengers within a convertible while it is moving.


Otherwise known as “antifreeze,” a substance which ensures that an engine remains at a cool enough temperature to operate without overheating. Most coolants are comprised of a mixture of water and ethylene glycol. This combination provides both a lower freezing point as well as a higher boiling point compared with normal water.

Cooled Seats

Installations which direct cooler air from a vehicle’s air conditioning system toward vehicle seats. Small holes within the center of a seat bottom direct cooled air onto the seat to ensure it remains cool and comfortable for passengers.

Cooling Fan and Shroud

A fan which pulls and directs cooled air through a vehicle’s radiator. Controlled via a mechanical, hydraulic, or electric system, the shroud itself creates a direct passage for air to flow between a vehicle radiator and its fan. This passage improves the fan’s overall effectiveness at providing cooling in these essential areas. Proper operation of the cooling fan and shroud prevents a vehicle from overheating and reduces the risk of related issues associated with this problem.

Cornering Brake Control

Used to prevent oversteer, this feature is used on antilock braking systems to apply sufficient brake force and proportion it based on the current driving circumstances. This control system is only equipped as a feature on some antilock braking systems based on specific vehicle years, makes, and models.

Cornering Lights

White driving lights positioned at either side of a vehicle’s front corners. These lights are specifically installed to improve drivers’ ability to successfully navigate a vehicle during the cornering process. The precise position of the lights allows for a much clearer view for cornering than otherwise possible.


Refer to “Certified Pre-Owned Vehicle” for more information.

Crankcase Breather

A ventilation device or system which provides a method for excessive pressure from the crankcase to be eliminated. Without this system in place, added pressure could cause damage to the crankcase and related components.

Crankcase Depression Regulator Valve

A valve used to decrease and prevent excess pressure buildup within the crankcase. Alongside the crankcase breather, these components ensure that pressure issues are mitigated within the crankcase installation. Overly high pressure could cause problems such as oil leakage past the seals and related damage.

Crankcase Ventilation Filter

Otherwise known as the “CCV,” this filter is used to catch foreign bodies and particulates from entering into the crankcase. Foreign contaminants within this system could lead to a decrease in crankcase efficiency. In extreme cases, this could lead to actual damage within the system.

Crash Test Ratings

A series of ratings which represent a vehicle’s overall performance in a variety of crash tests. These ratings are published by the respective organizations which enact the tests, and each company can vary based on location, type of vehicle being tested, and other factors.

Credit Score

One of the most important factors in determining a vehicle or purchase interest rate or overall creditworthiness and approval potential for the consumer. Multiple credit rating agencies provide scores based on an applicant’s overall creditworthiness. This score is based on a variety of factors such as income-to-debt ratio, total amount of outstanding debt, recently opened lines of credit, and more. An analysis of this data is provided within a credit report, and this is a major factor in determining whether or not a prospective buyer or lease holder will be approved for financing. It will also determine the specific terms of a lease or financing agreement such as monthly repayment terms and interest.

Credit Tier

The specific rating threshold consumers are placed based on their credit scores determined by credit-rating agencies. The specific level is determined by an applicant’s credit history and their rating from a variety of financial factors. These factors include the length of time for the oldest credit line, income-to-debt ratio, total amount of outstanding debt, number of recently opened lines of credit, and multiple other factors. The consumer’s credit tier provides a standard which helps to predict how lending companies or other financial institutions may view that person’s potential financial risk. Risk relates to the overall likelihood that an applicant will make their payments in full and on time toward a vehicle loan repayment. Depending on creditworthiness, tiers could include unclassified, bronze, silver, gold, and platinum.

Credit Union

A financial institution where account holders ultimately have ownership over the operation. Membership within credit unions is typically based on specific requirements or criteria that may relate to local community factors. This could include employment with a specific company, having a residence within a specific city, or being a member of a union.

Cruise Control

A vehicular system which helps to automatically control a vehicle’s speed. The specific speed of the cruise control is activated, deactivated, and adjusted by the driver with controls on vehicles equipped with this feature.

Crumple Zone

A specific section within a vehicle’s structure that is designed to absorb the force of an impact by collapsing in the event of a collision. This design helps to reduce the damage or injury potential for occupants of a vehicle when an accident occurs.

Curb Weight

The actual weight of a vehicle when it is “full” in normal operation. This includes all factors for weight fluctuations such as a full tank of fuel, all standard equipment installed, and all other fluids filled to their proper levels. This weight measurement does not include any additional cargo or passengers.

Curtain Airbags

Otherwise known as “head airbags,” these installations are used to help cover a vehicle’s side glass. The wide-spanning airbags help to protect occupant’s heads, faces, and limbs during these types of impacts. They may also be effective in protecting occupants by keeping their heads and extremities fully in the vehicle even in the case of a rollover. Curtain airbags are another element used to provide enhanced safety to everyone inside a vehicle.

Customer Cash Incentive

An actual cash payment which is made to buyers by the manufacturer. This payment is primarily used as a means to enhance a vehicle’s sales potential and improve the chances a customer will purchase it.

CV Joints

Short for constant velocity joints, these components are located on the ends of the drive axles. They work to transmit the engine’s power to the rest of the vehicle while allowing full movement of the suspension and full steering control by the driver. These joints are typically covered by black accordion-style boots which also contain lubricant to allow them to operate as their optimal levels. When these joints are not properly operating, the entire engine performance can be negatively affected.


A transmission which is equipped with a continuously variable drive ratio. Traditional transmission systems utilize a stepped gear ratio. The CVT differs from these conventional systems by maintaining a steady acceleration curve without any pauses or hiccups for gear changes. Depending on the vehicle which it is installed, a CVT offers a smoother transmission and gear shifting process compared with normal step-gear transmissions.

Cylinder Configuration

The layout of all the cylinders equipped within a vehicle’s engine.

Cylinder Deactivation

To help maximize a vehicle’s fuel efficiency, this feature enables engines to disengage and turn off two or more of their cylinders during operation depending on the specific driving circumstances. This feature is not available in all vehicles.

Cylinder Head Bolts

Bolts which are used to clamp onto the cylinder heads of an engine and connect them to the engine block. This adds an additional layer of stability between the cylinders and the engine block itself.