Car glossary
Car listings are full of jargon. Here is what every spec term actually means, in plain English, with live numbers from the Trimslate dataset where they help.
Engines and power
What the numbers under the hood actually mean for daily driving.
- Horsepower (HP)A measure of how much work an engine can do. More horsepower means quicker acceleration.
- TorqueTwisting force from the engine, felt as pull when you press the accelerator.
- Power-to-weight ratioHorsepower divided by curb weight, in hp per pound. The better predictor of how quick a car feels.
- CylindersThe chambers where fuel burns. Common counts are 3, 4, 6, and 8.
- Engine displacementThe total volume of an engine's cylinders, usually given in liters (like 2.0L).
- TurbochargedAn engine that uses exhaust-driven forced air for extra power from a smaller engine.
- SuperchargedAn engine with a belt-driven compressor forcing in extra air for immediate power.
- TwinchargedAn engine using both a supercharger and a turbocharger together.
- Naturally aspiratedAn engine that breathes air at normal pressure, with no turbo or supercharger.
- Start-stop systemAutomatically shuts the engine off at stops and restarts it when you release the brake.
Fuel economy and emissions
How the EPA measures efficiency, and how to read the ratings.
- MPG (miles per gallon)How far a vehicle travels on one gallon of fuel. Higher is more efficient.
- City MPGFuel economy in stop-and-go urban driving, usually the lowest of the three EPA figures.
- Highway MPGFuel economy at steady higher speeds, usually the best figure for gasoline cars.
- Combined MPGThe EPA's single overall figure, weighted 55 percent city and 45 percent highway.
- MPGeMiles per gallon equivalent: how far an EV travels on the energy in one gallon of gasoline.
- Annual fuel costThe EPA's estimate of a typical year of fuel, assuming 15,000 miles at average prices.
- CO2 grams per mileTailpipe carbon dioxide emitted per mile driven, measured by the EPA. Lower is cleaner.
- Eco score (greenhouse gas score)The EPA's 1 to 10 climate-impact score. A 10 is the cleanest.
- Real-world MPG (driver reported)The average MPG owners report from their own driving, collected by fueleconomy.gov.
- Smog ratingThe EPA's 1 to 10 score for smog-forming tailpipe pollution. Higher is cleaner.
- DieselAn engine type that compresses air to ignite fuel, prized for torque and highway economy.
- Flex fuel (E85)A vehicle that can run on E85 (up to 85 percent ethanol), regular gasoline, or any mix.
Hybrids and electric vehicles
Batteries, charging levels, and the vocabulary of electrified cars.
- Hybrid (HEV)Pairs a gasoline engine with an electric motor and a small self-charging battery.
- Plug-in hybrid (PHEV)A hybrid with a bigger battery you charge from an outlet, for 20 to 50 electric-only miles.
- Mild hybrid (MHEV)A small electric assist that smooths start-stop and aids the engine, but never drives alone.
- Electric vehicle (EV, BEV)Runs entirely on a battery and electric motors. No engine, no tailpipe.
- Kilowatt-hour (kWh)The unit of battery capacity. An EV's kWh number is its fuel tank size.
- Kilowatt (kW)A unit of power, used for EV motor output and charging speed. 1 kW is about 1.34 HP.
- Electric rangeHow many miles an EV or plug-in hybrid travels on battery power, as rated by the EPA.
- Regenerative brakingSlowing the car with the motor acting as a generator, sending energy back to the battery.
- Level 1 chargingCharging from a standard 120-volt household outlet. Slow: roughly 3 to 5 miles per hour.
- Level 2 charging240-volt charging, the standard home and workplace setup. Refills most EVs overnight.
- DC fast chargingHigh-power public charging that takes an EV from 10 to 80 percent in 20 to 45 minutes.
- Charge time (240V)Hours for a full charge on a 240-volt Level 2 connection, the standard home setup.
- One-pedal drivingStrong regenerative braking that slows the EV to a stop when you lift off the accelerator.
Drivetrain and transmission
Which wheels are driven and how power gets to them.
- DrivetrainWhich wheels the engine powers: front, rear, all four, or selectable four-wheel drive.
- All-wheel drive (AWD)Power flows to all four wheels automatically, with no driver input needed.
- Front-wheel drive (FWD)The engine powers the front wheels. The most common and usually most efficient layout.
- Rear-wheel drive (RWD)The engine powers the rear wheels. Favored for handling balance and towing.
- Four-wheel drive (4WD, 4x4)Driver-selectable power to all four wheels, built for off-road and heavy-duty work.
- TransmissionThe gearbox that matches engine speed to road speed: automatic, manual, or CVT.
- Automatic transmissionShifts gears for you using a torque converter. The default in modern vehicles.
- Manual transmissionYou shift gears yourself with a clutch pedal and stick. Increasingly rare.
- CVT (continuously variable transmission)An automatic with no fixed gears, tuned for smoothness and fuel economy.
- Dual-clutch transmission (DCT)An automated gearbox with two clutches for near-instant shifts, common in performance cars.
- Axle ratioThe final drive gearing between driveshaft and wheels, like 3.73. Higher pulls harder, lower cruises easier.
Size, weight, and capacity
Dimensions and ratings that decide what a vehicle can carry.
- WheelbaseThe distance between front and rear axles. Longer usually means a smoother ride.
- Curb weightWhat the vehicle weighs empty, with all fluids but no passengers or cargo.
- GVWR (gross vehicle weight rating)The maximum safe total weight of the loaded vehicle: itself plus people and cargo.
- Payload capacityThe total weight of passengers and cargo a vehicle can carry, GVWR minus curb weight.
- Towing capacityThe maximum trailer weight a vehicle is rated to pull safely.
- Cargo volumeLuggage or cargo space in cubic feet, measured behind the seats.
- Passenger volumeEPA-measured interior space for people, in cubic feet. More volume, roomier cabin.
- Ground clearanceThe gap between the ground and the lowest point of the chassis.
Safety and reliability
Crash ratings, recalls, and the other NHTSA records worth checking.
- NHTSA 5-Star Safety RatingsThe U.S. government's crash-test program. More stars means better crash protection.
- Rollover ratingNHTSA's star rating for rollover risk, based mostly on how top-heavy the vehicle is.
- Electronic stability control (ESC)Brakes individual wheels automatically to stop a skid. Standard on all cars since 2012.
- Forward collision warning (FCW)Alerts you when you are closing too fast on the vehicle ahead.
- Lane departure warning (LDW)Alerts you when the car drifts out of its lane without a turn signal.
- RecallA safety defect the manufacturer must fix for free, on NHTSA's record permanently.
- Technical service bulletin (TSB)A manufacturer's repair advisory to dealers for a known issue. Not a recall, not free.
- NHTSA investigationA federal probe into a suspected defect, often the step before a recall.
- Owner complaintsProblem reports owners file with NHTSA. A rough signal, not verified defects.
- Park outside warningAn active recall advising owners to park outdoors because of fire risk.
Shopping and ownership
Pricing terms, trims, and warranties decoded.
- MSRPThe manufacturer's suggested retail price: the sticker price before fees and negotiation.
- Invoice priceRoughly what the dealer paid the manufacturer for the vehicle. A negotiation reference.
- Destination chargeThe non-negotiable fee for shipping the vehicle from the factory to the dealer.
- Trim levelA factory-defined version of a model with a set bundle of equipment and price.
- Model yearThe vehicle's marketing year, which can differ from when it was actually built.
- Body styleThe vehicle's overall shape and type: sedan, SUV, hatchback, truck, van, or wagon.
- Basic warranty (bumper to bumper)Covers most factory defects for a set period, commonly 3 years or 36,000 miles.
- Powertrain warrantyLonger coverage for the engine, transmission, and drive components.
- Roadside assistanceManufacturer-paid help for breakdowns: towing, jump starts, lockouts, flat tires.
Data and sources
The public databases behind every figure on Trimslate.
- EPA (fuel economy data)The U.S. agency whose standardized tests produce every official MPG and range figure.
- vPIC (NHTSA vehicle database)NHTSA's public catalog of basic vehicle facts: make, model, body, engine, dimensions.
- Window sticker (Monroney label)The federally required label showing price, equipment, fuel economy, and safety ratings.