Used car dealers: jargon buster

APR (annual percentage rate): The real cost of the loan you take out to buy a car from a used car dealer.

Clocking: A scam whereby a disreputable used car dealer can wipe miles off the car's milometer to increase its value. Check that your used car dealer has verified the mileage.

Depreciation: All cars lose value as you drive them. Those that depreciate the least make the best used cars (the lowest-depreciating cars still lose around 50 per cent of their value after three years).

DVLA (Driver and Vehicle Licensing Agency): Where you must record changes of vehicle ownership.

Franchised dealer: Most car manufacturers sell approved used cars through their franchised dealers. These cars are usually less than three to four years old, and come with an MOT, full service history and warranted mileage.

FSH (full service history): What you want to see when you buy from a used car dealer.

Glass's Guide: A valuation guide used by used car dealers. To find out what a car is worth go to www.glass.co.uk or www.parkers.co.uk for a free valuation.

HPI: A vehicle data check that provides private car buyers, used car dealers, finance houses and the insurance industry with information on all UK registered vehicles. It can tell you if a vehicle has been stolen, previously written off or has outstanding finance on it. It also alerts buyers and used car dealers to potential mileage discrepancies.

MOT: Cars over three years old must have an MOT (Ministry of Transport) certificate to prove they're in a roadworthy condition.

MPG (miles per gallon): The number of miles a car can travel for every gallon of petrol in the tank. Usually a manufacturer or used car dealer will quote these figures for urban and motorway driving conditions.

Nearly new cars: There's no definition in the UK but used car dealers generally use the phrase to refer to cars under one year old.

Non-franchised dealers: A used car dealer that isn't linked to one of the main makes of car.

Retail Motor Industry Federation: A trade association for used car dealers.

V5: Registration document issued by the DVLA, giving the name and address of a vehicle's current owner plus the last two keepers. It also lists the car's colour, make, model, engine number and VIN (see below).

VIN (Vehicle Identification Number): The manufacturer's ID, stamped on a plate under the bonnet and/or etched on the windows. Ask your used car dealer to show you that the VIN matches the number on the V5.

Warranty: Offered by used car dealers to cover the vehicle for various unforeseen electrical and mechanical failures, the warranty usually includes the cost of repair and replacement of parts.