Glossary, A to Z.

Short definitions of the terms used across this site. Each links to the page that covers it in depth, and where series or sources use a term differently, the entry says so.

Get trained

This page explains the principles. It is not a substitute for instruction from a racing school or a sanctioning body's driver education program, and it does not replace the rules and tech requirements of the event you enter.

24 Hours of Le Mans: The endurance race first run in May 1923 on public roads south of Le Mans in France, organised by the ACO and now a round of the WEC. Crews of drivers take turns in one car, and several classes race at once. (Endurance and Le Mans)
9 and 3: Hands on the steering wheel at the 9 o'clock and 3 o'clock positions. HP Academy recommends it with the hands moving only for gear changes or in-car adjustments, and says shuffling the hands costs steering speed and accuracy. (Seating and hands)
ABP (Advanced Ballistic Protection): An optional, tougher version of an FIA 8859-2024 or 8860-2018 full-face helmet with a reinforced forehead panel. Under FIA Appendix L, Formula 1 and several other single-seater series require the ABP version. (Helmets)
ABS (anti-lock brakes): A system that pulses the brakes so the tyres keep turning and the car can still steer under hard braking. Coaches differ on track use: Driver61 aims to stay just short of ABS activation, while Ross Bentley says a highly refined system can be used fully. (Braking)
ACCUS: The body that acts as the FIA's national sporting authority in the United States, often written ACCUS-FIA. A 2018 ACCUS information sheet, still linked by SCCA, lists its member clubs as IMSA, IndyCar, NASCAR, NHRA, SCCA and USAC. (Governing bodies; Licences and schools)
ACO (Automobile Club de l'Ouest): The French club that organises the 24 Hours of Le Mans and runs the World Endurance Championship jointly with the FIA, according to the WEC's official site. (Endurance and Le Mans)
Aerodynamic and mechanical grip: Two sources of grip: aerodynamic grip comes from downforce pressing the tyres harder onto the road, and mechanical grip from the car's mass, tyres and suspension (Wikipedia, secondary). Downforce rises with the square of speed (same source), so aerodynamic grip grows quickly as speed rises. (How grip works)
Aeroscreen: IndyCar's cockpit protection, a polycarbonate screen in a titanium frame developed with Red Bull Advanced Technologies and introduced in 2020. (IndyCar; Safety evolution)
Apex: The point in a corner where the car comes closest to the inside edge, also called the clipping point and often marked by a curb. Ross Bentley points out that drivers also use "apex" for the minimum speed point, and that the two do not always coincide. (Racing line)
Appendix H: The part of the FIA International Sporting Code that covers supervision of the road (the track) and emergency services, including the flags, light panels and start lights used at FIA events. The 2026 edition was published on 23 June 2026. (Flags)
Appendix L: The part of the FIA International Sporting Code that covers international drivers' licences, medical examinations, drivers' equipment and driving conduct. The 2026 edition was published in June 2026. (Licences and schools)
Aquaplaning: When the tyre tread cannot clear standing water fast enough, so the tyre loses contact with the track surface, as Driver61 defines it. HP Academy warns that puddles that form in hollows, or appear suddenly in heavy rain, can cause it, often near the track edge. (Wet weather)
ASN: A country's national sporting authority for motorsport. Under FIA Appendix L, the ASN issues most international licences to its own drivers; the Super Licence is issued by the FIA itself. (Governing bodies)
Attack Mode: In Formula E, a race mode that gives more power than normal race trim; Gen3 Evo cars also use all-wheel drive in it (Wikipedia, secondary). (Formula E)
Autocross (Solo): A timed run around a short course laid out with traffic cones in a parking lot or airfield. SCCA calls its version Solo; the fastest time wins as long as the driver does not hit cones or go off course. (Autocross)
Balaclava: A fire-resistant hood worn under the helmet. It is one of the garments covered by the FIA's 8856 clothing standard, and SCCA's Race Experience rules require one (or a fire-resistant helmet skirt) for drivers with beards or mustaches. (Suits and underwear)
Bedding (brake pads): Bringing new brake pads up to working temperature in a controlled series of stops so they mate with the discs. Makers' procedures differ (EBC gives set stop counts and speeds, Ferodo a pressure build-up and temperature target), so follow the sheet supplied with your pads. (Track day car prep)
Black flag: Under FIA Appendix H, a black flag shown motionless with a car number orders that driver into the pits on the next approach. SCCA uses an open black flag with a number the same way, a furled black flag pointed at a car as a warning, and a "black flag all" at every station to stop the session. (Flags)
Black-and-white flag: An FIA flag divided diagonally into black and white halves, shown once to a driver as a warning for unsportsmanlike behaviour. SCCA gives the same kind of warning with a furled black flag instead. (Flags)
Blocking: Defending by repeatedly moving across in front of a car trying to pass. The FIA's Formula 1 Driving Standards Guidelines prohibit more than one change of direction to defend, and coach Ross Bentley's rule of thumb is also one defensive move, with any weaving counted as blocking. (Passing and racecraft)
Blue flag: A flag telling a driver that faster traffic is about to pass. The FIA uses light blue (in a race, for a car about to be lapped); SCCA's may be solid blue or carry a yellow or orange diagonal stripe; NASCAR's has a yellow stripe and warns slower cars that lead-lap cars are coming. (Flags)
Bracket racing: A form of drag racing in which each driver predicts an elapsed time (the dial-in) and the slower dial-in starts first by the difference, so top speed does not decide the result. Running quicker than the dial-in is a breakout. (Drag racing)
Brake bias: How braking force is split between the front and rear axles. Driver61 says the aim of adjusting it is for both axles to reach their grip limit at the same moment. (Braking)
Brake fluid (DOT 3, DOT 4, DOT 5.1): Grades of brake fluid defined by US federal standard FMVSS 116, which sets minimum dry and wet boiling points for each; DOT 4's minimums are higher than DOT 3's, and each wet figure is lower than the dry one. FMVSS 116 also requires containers to warn that absorbed moisture can cause brake failure. (Track day car prep)
Braking point: The spot where the driver starts braking for a corner, often judged from a fixed marker beside the track. Driver61 lists it with the turn-in point, apex and exit point as a corner's key reference points. (Braking; Learning a track)
Breakout: In bracket drag racing, running quicker than your own dial-in. If both drivers break out, the one closer to their dial-in wins, according to an NHRA brochure published by Sonoma Raceway. (Drag racing)
Bronze, Silver, Gold and Pro: Driver ratings used in sports car and GT racing to separate amateurs from professionals. IMSA's GTD class requires line-ups that mix professionals with Bronze- or Silver-rated amateurs, and GT World Challenge Europe splits its entry into Pro, Gold, Silver and Bronze classes (Wikipedia, secondary). (Touring and GT)
Caution: The US oval-racing term for a yellow-flag period: the field slows for an incident or debris and lines up behind the pace car. In NASCAR, pit road reopens once the cars are lined up. (NASCAR; Flags)
Chase (NASCAR): NASCAR Cup's championship format from 2026: after 26 regular-season races the top 16 in points contest a 10-race Chase, with one points reset at the start and no eliminations, and the points leader after the final race is champion. (NASCAR)
Check ride: An on-track assessment with a senior instructor riding along. NASA requires one before a driver moves up an HPDE group, and its Time Trial licence application asks for one unless the driver shows extensive open-passing or time trial experience. (Track days)
Chequered flag (checkered flag): The black and white flag that ends a session or race. In NASCAR a checkered flag also marks the end of a stage, though sources differ: Hendrick Motorsports describes a checkered flag, while RACER describes a green-and-white checkered flag for stage ends. (Flags)
Christmas Tree: The tower of lights that starts an NHRA drag race. Each lane has small pre-stage and stage lights, three large ambers, a green and a red; on a Pro Tree the ambers flash together, and on a Sportsman Tree they light one after another. (Drag racing)
CIK-FIA: The FIA's international karting body, created in 1962 and based in Geneva. Its international classes include OK and KZ (both points from Wikipedia, secondary). (Karting championships)
Clerk of the Course: The official in charge of running an FIA event on track. Appendix H reserves certain flags for the Clerk, including the red and chequered flags, and Formula 1 deploys the Safety Car on the Clerk's order. (Race weekend)
CMR and CMS: Children's motorsport helmet standards written jointly by Snell and the FIA (CMR2007, CMS2007 and the 2016 editions), used for young kart drivers. (Karting gear)
Co-driver: In rallying, the crew member who reads the pace notes aloud during each stage to warn the driver of corners, jumps and dips. (Rally and rallycross)
Code 60: An FIA neutralisation signalled by a purple flag with a white circle marked "60": every car must keep to 60 km/h around the whole course and may not overtake until a waved green flag ends it. (Flags)
Competition licence: The licence needed to race wheel to wheel. SCCA newcomers start on a Novice Permit and convert it to a Full Competition Licence after Drivers' School credit and three Regional race weekends; NASA newcomers go through its Competition School and a provisional licence. International licences are issued under FIA Appendix L. (Licences and schools)
Corner types: A way of ranking corners by what follows them. Ross Bentley credits Alan Johnson's 1971 book with Type 1 (leads onto a straight, so exit speed matters most) and Type 2 (follows a straight but does not lead onto one); PCA's Northern New Jersey Region adds a Type III for corners between other corners. (Racing line)
Data logger: A device that records what the car and driver did each lap. Driver61 says the channels that matter most to a driver are speed, throttle position, brake pressure and engine rpm, and recommends pairing a GPS logger with video. (Data and video)
Daytona 500: NASCAR's best-known race, first held in 1959 on the 2.5-mile Daytona International Speedway and the Cup season opener since 1982 (Wikipedia, secondary). (NASCAR)
Dial-in: The elapsed time a bracket drag racer predicts for their own run. The difference between two dial-ins sets the slower car's head start. (Drag racing)
Direct drive (sim wheel): A sim racing wheel base in which the motor turns the steering shaft directly, with no gears or belt. Fanatec calls it the top tier for force and detail, compared with gear-driven bases, which it calls low cost, and belt-driven bases (manufacturer's description). (Sim rigs)
Divebomb: A late, aggressive lunge up the inside under braking. KartClass calls it a last resort with a high risk of contact, and Driver61 lists the late dive as a high-risk overtake. (Passing and racecraft)
Double waved yellow: Under FIA Appendix H, two yellows waved at a post, meaning the track is wholly or partly blocked or marshals are working there: drivers slow significantly, do not overtake, and in practice or qualifying must abandon the lap. In SCCA-style US club flagging, Race Services Inc. says two motionless yellows at every station signal a full course yellow instead. (Flags)
Double-apex corner: A corner with two clipping points. Ross Bentley notes it still has only one minimum speed point, and coach Adam Brouillard advises against accelerating and then slowing again between the two apexes. (Racing line)
Downforce: Vertical force from a car's aerodynamic design that presses it onto the track, adding grip for cornering, as IndyCar defines it. Wikipedia (secondary) adds that it rises with the square of speed and usually costs drag. (How grip works)
Drafting: Following closely behind another car to cut aerodynamic drag, which IndyCar says is common on ovals and sets up passes. (Open-wheel; Passing and racecraft)
Drifting: A judged, not timed, discipline that the FIA describes as deliberately triggered oversteer, scored on line, angle, style and speed. In tandem battles a pair runs twice, swapping lead and chase. (Drifting and time attack)
DRS and Overtake Mode: DRS was Formula 1's overtaking aid. For 2026 it was replaced by Overtake Mode, which gives a car within one second of the car ahead at a detection point extra electrical power for the next lap. (Formula 1)
Early apex: Turning in early and reaching the inside of the corner too soon, which allows a faster entry but leaves the car running out of road and delaying the throttle on exit. Wikipedia (secondary) and HP Academy both describe it as a common novice mistake, though KartClass says it can suit closely spaced corners. (Racing line)
ECE 22: The European road helmet standard. UK retailer Demon Tweeks says ECE road helmets are not approved for motorsport, yet some track-day and HPDE organisers accept them (NASA Speed News reports that NASA's 2026 HPDE rules name ECE 22.06) while others, including SCCA, do not. Check your event's rules. (Helmets)
Elapsed time (ET): In NHRA drag racing, the time from leaving the staging beams to crossing the finish line, measured separately for each lane. (Drag racing)
Eyes up: The coaching reminder to look far ahead rather than just in front of the car. Dion von Moltke of Blayze calls it the phrase most used in high-performance driver education, because drivers tend to steer where they look. (Vision)
FHR (frontal head restraint): The FIA's term for a head and neck restraint: a device worn on the shoulders and tethered to the helmet that holds the head back relative to the torso in a frontal or angled crash, to cut neck loads. FIA-approved devices are built to the FIA 8858 standard. (Head and neck restraints)
FIA (Fédération Internationale de l'Automobile): The governing body of world motor sport, which also represents motoring organisations. It began in Paris in 1904 as the AIACR, an association of national automobile clubs, took the FIA name in 1946, and runs world championships including Formula 1, the WRC, the WEC and Formula E. (Governing bodies)
FIA 8853: The FIA standard for safety harnesses (seat belts); the current version is 8853-2016. (Seats and harnesses)
FIA 8855 and 8862: FIA standards for racing seats. The FIA says the 2021 version of 8855 is much stronger than the 1999 version, and 8862-2009 is its "advanced" seat standard. (Seats and harnesses)
FIA 8856: The FIA standard for drivers' fire-resistant clothing: overalls, underwear, balaclavas, socks, gloves and shoes. The 2018 version replaced 8856-2000, and unlike SFI suit ratings it is pass or fail with no numbered levels, according to Alpinestars. (Suits and underwear)
FIA 8858: The FIA standard for FHR (head and neck restraint) devices, their tethers and the matching helmet anchorages, in 2002 and 2010 versions. (Head and neck restraints)
FIA 8859 and 8860: The FIA's two families of car racing helmet standards: 8859 ("Premium Helmet", 2015 and 2024 versions) and 8860 (the "advanced" helmet, 2010 and 2018 versions). Which versions an event accepts is set by FIA Technical List 25, Appendix L and the event's own rules. (Helmets)
FIA 8877 and 8870: FIA karting standards: 8877-2022 covers karting overalls, gloves and shoes, graded for abrasion rather than fire, and 8870-2018 covers a chest and rib protector worn under the overall. (Karting gear)
Fire suppression system: An extinguisher system plumbed into the car, as opposed to a hand-held bottle, fired by a button the driver can reach and marshals can reach from outside. An FIA safety bulletin says its main job is to slow a fire so the occupants have more time to get out. FIA standards include 8865-2015 for closed cars and 8876-2022 for open cockpits. (Cages and fire safety)
Force feedback: Resistance and vibration that a sim racing wheel generates through its motor to reproduce what the car is doing. Wheel bases deliver it through gears, a belt or a direct-drive motor. (Sim rigs)
Formation lap: The lap before a standing start in which the cars circulate and then form up on the grid. Under FIA Appendix H, a green flag waved from the back of the grid then shows that every car is stationary. (Race weekend)
Formula 2 and Formula 3: The FIA single-seater series on the ladder below Formula 1. Formula 2 began in 2017 as a rebrand of GP2 and is the last step before F1, and all teams in each series use the same Dallara chassis (Wikipedia, secondary). A weekend has a shorter sprint race and a longer feature race that pays Formula 1-style points. (Open-wheel)
Friction circle: Also called the traction circle: the idea that a tyre has one maximum total grip, shared between cornering and braking or accelerating, so using more for one leaves less for the other (Wikipedia, secondary). (How grip works)
Full Course Yellow (FCY): A neutralisation of the whole track. At FIA events it is shown with a yellow flag and an "FCY" board at the marshal posts; in SCCA-style US club racing, Race Services Inc. says it is two motionless yellows at every station, called only by the Operating Steward. (Flags)
Geometric line: The widest, shallowest arc through a corner, using the full track width with the apex in the middle of the turn. Driver61 and HP Academy say it is fastest only for a corner taken in isolation, which real circuits rarely offer. (Racing line)
Grand Prix: A major race, today above all a round of the Formula 1 World Championship; the Automobile Club de France ran the first Grand Prix in 1906. An F1 Grand Prix weekend normally runs Friday to Sunday with practice, qualifying and the race. (Formula 1; Early racing)
Green flag: Under FIA Appendix H, a green flag waved at the post after an incident means the track is clear, and it can also start a warm-up lap or practice session. SCCA Time Trials says it shows the green only at start/finish, meaning the course is clear and competition is under way. (Flags)
Ground effect: Downforce made by shaping the underside of the car so that air speeds up and pressure drops beneath it, aiming for grip with less drag than wings (Wikipedia, secondary). Formula 1 banned it from 1983 and brought it back in 2022. (Technology history)
GT racing (GT3 and GT4): Racing for two-seat sports cars derived from production models. Wikipedia (secondary) calls GT3 the most popular class, with GT4 a step below; GT3 cars race in IMSA's GTD classes, the WEC's LMGT3 class, DTM and GT World Challenge. (Touring and GT)
GTD and GTD PRO: IMSA's two GT3 classes. GTD PRO (since 2022) is for all-professional crews, while GTD is pro-am, mixing professionals with rated amateurs. (IMSA)
GTP: IMSA's top class since 2023: closed-cockpit hybrid prototypes built to LMDh (and LMH) rules, so the same cars can also race in the WEC's Hypercar class. (IMSA)
Halo: The FIA's Additional Frontal Protection for single-seater cockpits, built to FIA standard 8869-2018. The FIA introduced it in 2018 and it is now mandatory in all FIA single-seater championships. (Safety evolution)
HANS (head and neck support): The best-known head and neck restraint, designed by engineer Robert Hubbard in the early 1980s and on sale from 1990, according to SCCA. It is made by HANS Performance Products and sold by Simpson, and comes in different collar angles to suit upright or reclined seating positions, according to retailer GSM Performance. (Head and neck restraints; Safety evolution)
Harness: A multi-point racing seat belt (5, 6 or 7 points) that holds the driver into the seat. SFI-certified harnesses are built to SFI 16.1 or 16.5 (HMS Motorsport says 16.6 was mandated in NASCAR's top series), and FIA ones to FIA 8853. (Seats and harnesses)
Head and neck restraint (HNR): A device that limits how far the head can move forward relative to the body in a crash; the FIA calls it an FHR. Devices are certified to SFI 38.1, FIA 8858 or both. Age and recertification rules differ by standard, so check the label and your event's rules. (Head and neck restraints; Gear expiry checker)
Heel-toe: A manual-gearbox technique in which the right foot brakes and blips the throttle at the same time while the left foot works the clutch, so a downshift can happen during braking without upsetting the car (Wikipedia, secondary; HP Academy). (Heel-toe)
Hillclimb: A timed run up a closed hill or mountain road. The Pikes Peak International Hill Climb in Colorado covers 12.42 miles and 156 turns, and SCCA runs HillClimb as a form of Time Trials. (How racing works)
Homologation: Formal approval by a sanctioning body, usually the FIA, that a product or car meets a set standard. FIA-homologated gear appears on the FIA's Technical Lists and carries an FIA label; the FIA notes that a homologation end date is the last date a product may be made, not a use-by date. (Equipment)
HPDE (High Performance Driver Education): Events where enthusiasts drive their own cars on road courses with instruction. NASA runs four HPDE groups, from HPDE 1 with one-on-one instruction up to HPDE 4 for experienced drivers, and says no group has a speed limit. (Track days)
Hybrid (energy recovery): A system that captures energy under braking and deploys it later as extra power. IndyCar added one in 2024 and uses it at every track, and Formula 1's 2026 power units split their output roughly half electric and half combustion. (Technology history)
Hypercar: The top class of the World Endurance Championship and Le Mans since 2021, open to prototypes built to either the LMH or LMDh rules (Wikipedia, secondary). Hypercars compete for overall pole and victory at Le Mans. (Endurance and Le Mans)
Hyperpole: The knockout qualifying used at the 24 Hours of Le Mans. For 2026, the top cars in each class from qualifying went to Hyperpole 1, and a smaller group then fought for pole in Hyperpole 2. (Endurance and Le Mans)
IMSA: The International Motor Sports Association, the US sports car sanctioning body founded in 1969, which runs the WeatherTech SportsCar Championship (including the Rolex 24 at Daytona) and several support series. Wikipedia (secondary) describes it as a NASCAR subsidiary. (IMSA)
Indianapolis 500: IndyCar's biggest race, first run in 1911 on the 2.5-mile Indianapolis Motor Speedway oval (Wikipedia, secondary). (IndyCar)
IndyCar: The US open-wheel series and its sanctioning body, which began as the Indy Racing League in 1994 and took the INDYCAR name in 2011. It races a spec Dallara chassis on ovals, road courses and street circuits, and its centrepiece is the Indianapolis 500 (Wikipedia, secondary; IndyCar for the track types). (IndyCar)
Joker lap: In rallycross, a longer alternative route that each driver must take once per race. In the 2024 World RX format, skipping it costs a championship point. (Rally and rallycross)
Kill switch: A master switch that cuts all of a race car's electrical circuits and stops the engine. FIA Appendix J Article 253 calls it a general circuit breaker and requires it to work from inside and outside the car, with the outside switch marked by a red spark in a blue triangle. (Cages and fire safety)
KZ and OK (karting classes): The two main international karting classes of the FIA Karting World Championship: OK is a direct-drive kart with no gearbox, and KZ is the top gearbox class (Wikipedia, secondary). (Karting)
Late apex: Turning in and reaching the inside of the corner later than on the geometric line, so the exit is straighter and the throttle can come on earlier. Driver61 calls this its "ideal line" and says it trades a lower minimum speed for a better exit. (Racing line)
Lead-follow: Laps in which a novice follows an instructor's car to learn the line. NASA uses it as one form of HPDE 1 instruction, and racing schools such as Skip Barber include it in their courses. (Track days)
Left-foot braking: Braking with the left foot instead of moving the right foot across from the throttle. Coaches disagree on its value: Ross Bentley says a skilled left-foot braker usually wins, while Dion von Moltke says it is not faster for most braking zones. (Braking)
Lift-off and power oversteer: Two kinds of oversteer Driver61 names. Lift-off oversteer is triggered by lifting off the throttle mid-corner (HP Academy explains that a lift shifts load toward the front), and Driver61 calls it snappy; power oversteer comes from too much throttle out of a corner in a rear-wheel-drive car. (Understeer and oversteer)
LMDh and LMH: The two sets of prototype rules allowed in the WEC's Hypercar class: Le Mans Hypercar (LMH) and LMDh. IMSA's GTP class uses LMDh rules, which is why the same cars can race on both sides of the Atlantic. (Sports cars and endurance)
LMGT3: The GT class of the WEC and Le Mans, for production-based GT3 cars, which replaced the GTE classes from 2024 (Wikipedia, secondary). (Endurance and Le Mans)
LMP2: A prototype class that sits between the top prototypes and the GT cars in pace. RACER's IMSA class guide describes closed-cockpit cars from a small set of approved chassis makers, and Wikipedia (secondary) says the class uses one spec Gibson V8 engine. (Sports cars and endurance)
Load cell pedal: A sim racing brake pedal that measures how hard you press rather than how far the pedal moves. Simucube argues this matches real braking and helps build muscle memory (manufacturer's claim). (Sim rigs)
Lock-up: A wheel stopping turning under braking so the tyre slides. A sliding tyre has less grip than a rolling one and cannot steer the car, which is why threshold braking aims to stay just short of it (Wikipedia, secondary). (Braking)
M6 anchors (helmet posts): Threaded inserts in a helmet shell that take the posts for a head and neck restraint's tethers. Snell SA2015 and SA2020 helmets must have them, and SCCA says all SA helmets made after 2020 do. (Helmets)
Maintenance throttle: Ross Bentley's term for the throttle needed to hold a steady speed, for example through a long corner. He says it keeps the car balanced front to rear. (Weight transfer)
Marbles: Bits of tyre rubber that collect off the racing line and reduce grip, in IndyCar's definition. (Racing line)
Marshal (corner worker): A trackside official at a marshal post who shows flags to drivers and works at incidents. FIA Appendix H sets out the flags marshal posts use. In US club racing the job is done by flaggers and corner workers, from groups such as Race Services Inc. (Flags)
Meatball flag: A black flag with an orange (or, in SCCA usage, red) ball, shown with a car number when that car has a mechanical problem and must go to the pits. Under FIA Appendix H the car may rejoin only once the chief scrutineer is satisfied. (Flags)
Motorsport UK: The national governing body for four-wheeled motorsport in the UK, which issues competition licences and event permits. (Governing bodies)
NASA (National Auto Sport Association): A US club founded in 1991 and based in Las Vegas that runs HPDE track days, Time Trial, wheel-to-wheel road racing and autocross. Its rulebook is the Club Codes and Regulations (CCR). (Governing bodies; Track days)
NASCAR: The National Association for Stock Car Auto Racing, based in Daytona Beach, Florida, whose top level is the Cup Series. Sources give different founding dates: Britannica says 1947, while Wikipedia (secondary) gives 21 February 1948. (NASCAR; Stock cars)
NHRA: The National Hot Rod Association, the drag racing body founded in 1951 by Wally Parks. Its professional series has four classes, and most participants race in its Sportsman programs (Wikipedia, secondary). (Drag racing series)
Opposite lock: Steering against the direction of a slide, also called countersteer, which Driver61 names as the principle for stopping over-rotation in oversteer. Virtual Racing School warns that unwinding it too late can send the car the other way. (Understeer and oversteer)
Oversteer: At the limit, the rear tyres lose grip first and the car turns more than the driver asked, rotating toward the inside of the corner. It is also called "loose". Formally, SAE J670 and ISO 8855 define it as a negative understeer gradient (Wikipedia, secondary). (Understeer and oversteer)
Pace car: The US name for the course car that leads the field at reduced speed under a caution. Elsewhere it is called the Safety Car. (Race weekend)
Pace notes: A rally crew's own description of each stage, written while driving it slowly during the recce. The co-driver reads them aloud during the stage to warn of corners, jumps and dips. (Rally and rallycross)
Pit lane speed limit: A maximum speed enforced in the pit lane, for example 60 km/h at the 2026 Lone Star Le Mans WEC round. WEC briefing notes add a commitment line at pit entry, after which a car must enter the pits, and SCCA Time Trials tells drivers not to cross the blend line at pit exit. (Race weekend)
Point-by: A signal from the driver ahead allowing a following car to pass, usually an arm out of the window pointing to the side the passer should use (SCCA Time Trials). SCCA Time Trials requires beginner, novice and intermediate drivers to use one for every pass. (Track days; Passing and racecraft)
Pole position: First place on the starting grid, earned by the fastest qualifier. In Formula 1 it is decided in Q3, the last part of qualifying. (Race weekend)
Power Stage: The final stage of a WRC rally, where the five fastest crews earn extra championship points. (Rally and Dakar)
Primary and alternate tyres: IndyCar's two dry tyres for road and street courses: the harder primary (black sidewall) and the softer, grippier alternate (red sidewall), which wears faster. Drivers must use both in each race. (IndyCar)
Prototype: A purpose-built sports racing car, as opposed to a production-based GT car. The top classes at Le Mans and in IMSA are prototype classes. (Sports cars and endurance)
Push-to-pass: A driver-controlled power boost that IndyCar allows on road and street courses, alongside its hybrid assist. (IndyCar)
Qualifying: Timed sessions that set the starting grid. Formula 1 uses a three-part knockout (Q1, Q2, Q3), dropping six cars in each of the first two parts in 2026; sources differ on the 2026 length of Q3, which The Race gives as 12 minutes and Honda as 13. (Race weekend)
R-compound tyre: A competition tyre with much shallower tread, a stiffer casing and a sticky compound. A Maxxis engineer (in a sponsored Grassroots Motorsports article) says they warm quickly and grip hard but wear fast and work poorly when wet or cold. (Track day car prep)
Racing line: The fastest path through a corner, which Driver61 says depends on the corner, the straight after it and the car. It usually uses the full width of the track: in from the outside, clip the inside at the apex, out to the outside again. (Racing line)
Rallycross: Short races on circuits that mix asphalt and gravel, which Peugeot Sport describes as a blend of rallying and circuit racing. Every driver must take the longer joker lap once per race. (Rally and rallycross)
Recce: Short for reconnaissance: before a rally, crews drive the stages slowly in road cars and write their pace notes. (Rally and rallycross)
Red flag: Stops a session or race. Under FIA Appendix H cars slow and go to the red-flag line (or the pits in practice) without overtaking; SCCA Time Trials has drivers stop at the side of the track near a staffed station until released; in NASCAR, teams may not work on the cars while it is out. (Flags)
Red light (drag racing): Leaving the start before the green light, which disqualifies the driver in that race ("redlighting"). (Drag racing)
Rev matching (blip): Raising engine speed with a quick press of the throttle during a downshift so it matches the lower gear before the clutch comes up. HP Academy says skipping it can briefly lock or slow the driven wheels and unsettle the car. Some road cars now do it automatically (Wikipedia, secondary). (Heel-toe)
Roll cage: A tube structure built into the car's cabin to protect the occupants. FIA Appendix J Article 253 requires a homologated or certified cage, with FIA 8857-2001 flame-retardant padding on the tubes its drawing specifies, and forbids modifying a homologated one. (Cages and fire safety)
Run group: One of the groups a track day splits drivers into by experience, each with its own sessions on track. SCCA Track Days use Novice, Intermediate and Advanced groups, and NASA's HPDE uses groups 1 to 4. (Track days)
Safety Car: A course car that leads the field at reduced speed. In Formula 1 it comes out on the Clerk of the Course's order when people are in immediate danger but the race need not be stopped, and every lap behind it counts as a race lap. US oval racing calls it the pace car. (Race weekend)
SCCA: The Sports Car Club of America, founded in 1944, which runs Club Racing (wheel-to-wheel road racing), Solo (autocross), RallyCross, Time Trials, HillClimb, Track Days and professional events through SCCA Pro Racing. Its road racing rulebook is the GCR. (Governing bodies)
Service park: The only place a WRC team may do major work on a rally car, within fixed time windows; arriving late or overstaying brings time penalties. (Rally and rallycross)
SFI: The SFI Foundation, which publishes specifications for racing safety gear, each with its own number: 3.2A for driver suits, 3.3 for gloves, shoes and other accessories, 16.1 and 16.5 for harnesses, 27.1 for window nets, 31.1 for helmets and 38.1 for head and neck restraints. (Equipment)
SFI 3.2A rating: The number after the slash on an SFI driver suit label (such as /1, /5 or /20), which rises with the suit's thermal protection (TPP). Published figures with SFI input put a /5 suit at about 10 seconds before a second-degree burn, and a /20 at about 40. (Suits and underwear)
Single-seater (open-wheel): A race car with one seat and uncovered wheels, usually with wings for downforce (Wikipedia, secondary). Formula 1, IndyCar, Formula 2 and Formula E are single-seater series. (Open-wheel)
Slip angle: The angle between where a tyre is pointing and where it is actually travelling. The tyre's flexing creates it, and it is what produces cornering force (Wikipedia, secondary). (How grip works)
Slow in, fast out: The old advice to enter a corner slowly and exit fast. Ross Bentley says it works more often than not but backfires if taken to extremes, since a very slow entry gives away more speed than an early throttle can win back. (Racing line)
Snap oversteer: A sudden switch from understeer to oversteer, which Virtual Racing School says is made worse when the driver has added extra steering lock during the understeer. (Understeer and oversteer)
Snell: The Snell Memorial Foundation, which writes helmet standards and certifies helmets that pass them. Each standard is named by a letter code and the year it took effect, and certified helmets carry a Snell label inside. (Helmets)
Snell K: Snell's kart racing helmet standard (K2025 is current). Pegasus Auto Racing describes it as using the same tests as SA but without the fire-retardant lining. (Karting gear)
Snell M: Snell's motorcycle helmet standard. Snell says it has no flammability test and allows a wider field of vision than SA, and some organisers accept it for autocross or track days while others do not. (Helmets)
Snell SA: Snell's standard for competitive car racing (SA2025 is current, following SA2020 and SA2015); SCCA explains the letters as "Special Application". Snell says SA adds a flammability test that its motorcycle standard lacks. Which SA years an event accepts is set by the event, not by Snell. (Helmets; Gear expiry checker)
Spec series: A series where every team uses the same chassis or key parts. IndyCar, for example, uses a spec Dallara chassis, with Chevrolet and Honda engines (Wikipedia, secondary). (Open-wheel)
Special stage: A timed section of closed road in a rally; untimed road sections on public roads link the stages, and the winner has the lowest total stage time. (Rally and rallycross)
Sprint (Formula 1): A short Saturday race of about 100 km, roughly a third of a Grand Prix, with no mandatory pit stop and points for the top eight. On 2026 sprint weekends it replaces the third practice session. (Formula 1)
Stage (NASCAR): One of the three segments of a 2026 NASCAR Cup race. The top 10 at the end of stages 1 and 2 score points, from 10 down to 1. (NASCAR)
Staging: Rolling up to the start line of a drag race. In NHRA racing the pre-stage light comes on when the car is about 7 inches behind the line, and the stage light when the front tyres are on it. (Drag racing)
Standing and rolling starts: In a standing start the cars wait stationary on the grid and go when the red start lights go out; in a rolling start they are already moving when the start is given, and FIA start lights change from red to green. (Race weekend)
Stewards: The officials who judge incidents and hand out penalties. The FIA's Formula 1 Driving Standards Guidelines say stewards look at each incident as a whole, and WEC briefing notes let them penalise drivers who do not slow in yellow zones. (Race weekend)
Stock car: A car that resembles a standard American production model, raced mostly on paved ovals, as Britannica describes it. Modern NASCAR stock cars are purpose-built and only loosely resemble road cars (Wikipedia, secondary). (Stock cars)
Super Licence: The FIA licence needed to race in Formula 1, issued by the FIA itself. Appendix L requires a current Grade A licence, a minimum age and points earned in listed championships, among other conditions. (Licences and schools)
Supplementary Regulations: The rules published for one particular event. SCCA notes they say whether an event uses all flags or only some, or lights instead, and FIA Appendix H lets them add light panels alongside flags. (Flags)
Surface flag: A yellow flag with red vertical stripes, held still to warn of reduced grip from oil, water or debris. The FIA says it is shown for at least four laps, depending on circumstances, unless the surface recovers; SCCA says it may be withdrawn once everyone has seen it, even if the hazard remains. (Flags)
Switchback: An overtake in which the attacker goes wide on entry, then cuts back under the defender on exit to get on the throttle first. Driver61 notes that a driver defending the inside compromises his own exit and is exposed to it. (Passing and racecraft)
Tech inspection (scrutineering): A safety check of the car, and often the driver's helmet, before it may go on track. At SCCA autocrosses (as SCCA's Buccaneer Region describes them) it covers items such as tyres, brakes, lug nuts, a secured battery and loose objects removed; at FIA events the inspectors are called scrutineers. (Track day car prep; Autocross)
Technical List (FIA): The FIA's published lists of approved standards and homologated products, such as List 25 (recognised helmet standards), List 29 (FHR systems) and List 74 (8856-2018 clothing). (Equipment)
Threshold braking: Braking at the edge of grip: as hard as possible without locking the wheels or triggering ABS, in Blayze coach Dion von Moltke's definition. (Braking)
Time attack: Competition for the single fastest lap, with cars sent out at intervals rather than racing wheel to wheel. (Drifting and time attack)
Time trial: Lapping against the clock with other cars on track, but not wheel-to-wheel racing; SCCA says passing happens carefully in passing zones with point-bys. NASA scores its Time Trial on each driver's fastest lap of the day. (Track days)
Timeslip: The record a drag racer gets after each run, with elapsed times at 60 feet, 330 feet, the eighth mile, 1,000 feet and the quarter mile, plus speeds and reaction time (how quickly the driver responded to the green light). (Drag racing)
Top Fuel and Funny Car: The NHRA's two nitromethane-fuelled professional classes. Wikipedia (secondary) says they race 1,000 feet rather than the full quarter mile. (Drag racing)
Touring car: A four-seat race car derived from a production model, with limited aerodynamics that make close racing easier (Wikipedia, secondary). BTCC and Supercars are touring car series. (Touring and GT)
TPP (Thermal Protective Performance): A measure of how long fire-resistant clothing protects against a second-degree burn under combined flame and radiant heat. It is the basis of SFI 3.2A suit ratings. (Suits and underwear)
Track day: A non-competitive event where drivers lap a circuit in groups, usually in their own cars. SCCA stresses that its Track Days are not races; its national Track Night in America program runs at more than 30 tracks. (Track days; Track day checklist)
Trail braking: Carrying some brake pressure past the turn-in point and releasing it gradually toward the apex. Ross Bentley counts any braking that continues past turn-in, and coaches disagree on why it helps: most say it keeps load on the front tyres, while Adam Brouillard frames it as following the friction circle. (Braking)
Treadwear (UTQG): A US tyre grade measured on NHTSA's test course against a reference of 100: NHTSA's example is that a tyre graded 150 should wear one and a half times as well as one graded 100. Some classes, such as NASA's TT Street, require 200 treadwear or higher. (Track day car prep)
Triple Crown of Motorsport: An unofficial honour for winning the Indianapolis 500, the 24 Hours of Le Mans and the Monaco Grand Prix; an older version swaps Monaco for the F1 world title. Graham Hill is the only driver to have done it under either version (Wikipedia, secondary). (Notable drivers)
Turn-in point: Where the driver starts steering into a corner. Driver61 says turning in too late costs corner speed and too early costs exit speed. (Racing line)
Understeer: At the limit, the front tyres lose grip first and the car runs wide of the line the driver steered for. It is also called "push" or "plow". Formally, SAE J670 and ISO 8855 define it as a positive understeer gradient (Wikipedia, secondary). (Understeer and oversteer)
Virtual Safety Car (VSC): A way to neutralise a session without sending out a course car, used in Formula 1 when double waved yellows are needed but a Safety Car is not. F1 introduced it for 2015 after Jules Bianchi's accident at the 2014 Japanese Grand Prix, and 2026 WEC briefing notes set a VSC speed of 80 km/h. (Race weekend)
WEC (World Endurance Championship): The FIA world championship for sports car endurance racing, begun in 2012 and run jointly by the FIA and the ACO; the 24 Hours of Le Mans is one of its rounds. (Endurance and Le Mans)
Weight transfer (load transfer): The shift of load between the tyres when a car brakes, accelerates or corners: forward under braking, rearward under acceleration, outward in a turn (Wikipedia, secondary). (Weight transfer)
Wet line: A path off the normal dry line used when the track is wet, because the rubber laid on the dry line becomes slippery. Coaches differ on how far to move: HP Academy generally avoids the dry line, while Dion von Moltke advises starting on it and adjusting. (Wet weather)
Wheel-to-wheel racing: Racing in which cars compete directly on track and may overtake one another, as opposed to time trials, where drivers race the clock, or track days, which are not competitions. SCCA says its time trials are not wheel-to-wheel competition and its track days are not races. (How racing works)
White flag: A flag whose meaning depends on where you race. Under FIA Appendix H it warns of a much slower vehicle ahead; SCCA shows it two stations before a slow car or emergency vehicle; in NASCAR and much US oval racing it means one lap to go. (Flags)
Window net: A mesh net fitted across the window opening of a closed race car with a cage. FIA Article 253 makes nets mandatory in circuit competition, and Motorsport Australia requires a one-hand quick release. SFI's specification for window nets is 27.1. (Seats and harnesses)
WRC (World Rally Championship): The FIA's world championship for rallying, run over several days of timed special stages on surfaces from asphalt to gravel and snow. Its top class is Rally1, and Rally2 cars compete in WRC2. (Rally and Dakar)
Yellow flag: A danger warning: slow down and do not overtake. The FIA distinguishes a single waved yellow (hazard beside or partly on the track) from a double waved yellow; SCCA distinguishes a standing (motionless) yellow from a waving one. (Flags)

Sources