Car & VIN glossary

Plain-language meanings for the car, VIN and used-car-buying terms you'll meet on CarVinVin and in any listing. No jargon.

VIN (Vehicle Identification Number): A car's unique 17-character code — letters and numbers, never I, O or Q. Every vehicle has exactly one; it identifies the make, model, year and factory.
WMI (World Manufacturer Identifier): The first three characters of a VIN. They identify the manufacturer and the country where the vehicle was built.
Check digit: The 9th VIN character, calculated by the ISO 3779 formula to catch typos. US-market VINs must carry a valid one; many cars built for other markets do not.
Model year: The year a vehicle's design is sold as, encoded in the 10th VIN character. It can differ from the calendar year the car was actually built.
Safety recall: An official notice that a vehicle has a safety defect the manufacturer must repair — almost always for free, often with no time limit.
DTC (Diagnostic Trouble Code): A standardized OBD-II code such as P0420, stored when the check-engine light comes on. It points to the system at fault, not the exact part.
Odometer: The instrument that records a vehicle's total distance travelled. Mileage is a key factor in a used car's value and expected wear.
Odometer rollback: Illegally winding back the recorded mileage to make a car look less used than it is. Also called clocking — a common used-car fraud.
Salvage title: A title brand given when an insurer declares a vehicle a total loss. Salvage cars are cheaper but hard to insure and resell.
Rebuilt title: A salvage vehicle that has been repaired and re-registered. Only as safe as the repair quality, which should be independently inspected.
Flood damage: Water damage that corrodes wiring and electronics for years after a car looks dry. Often hidden, and a serious long-term risk.
Lemon / manufacturer buyback: A vehicle the maker had to repurchase because it could not fix a fault under warranty. The defect may or may not have been resolved.
Title brand: A permanent label on a vehicle title after major damage or a buyback (salvage, rebuilt, flood, lemon). It follows the car and lowers its value.
Write-off / total loss: When repair costs exceed a vehicle value, so the insurer pays it out instead of fixing it. It usually leads to a salvage title.
NHTSA: The US National Highway Traffic Safety Administration. Its public vPIC database powers free VIN decoding and official safety-recall data.
Trim level: A named version of a model with a specific set of features and engine (for example Base, Sport or Limited). It affects value and equipment.
Body style: The shape and configuration of a vehicle — sedan, hatchback, SUV, pickup and so on. It is decoded from the VIN.
Drivetrain: Which wheels the engine powers: front-wheel (FWD), rear-wheel (RWD) or all-wheel drive (AWD). It affects handling, cost and economy.
Transmission: The gearbox that transfers engine power to the wheels — manual, automatic or CVT. A major and expensive component to check.
MOT: The United Kingdom's annual roadworthiness and safety test. MOT history can reveal past mileage readings and recurring faults.
Curbstoning: An unlicensed dealer posing as a private seller to offload problem cars and dodge consumer protections. Beware sellers handling many cars.
VIN cloning: Putting a legitimate car VIN onto a stolen or written-off one to hide its history. Check the VIN matches in every location and on the papers.