New to NASCAR? Here are terms to know as you watch the Iowa Corn 350 at Iowa Speedway

Will Sunday's Iowa Corn 350 be your first time watching NASCAR? Here are some terms to know before Sunday's race.

Green flag: The flag signifying the start of the race and to signal restarts.

Yellow flags/caution: Yellow warns drivers there has been an on-track incident and they must slow down to allow safety crews access to the track.

Red flag: A flag stopping action to repair damage from crashes or to wait out bad weather.

White flag: Signifies one more lap to go in a race.

Checkered flag: The race is over when cars cross the start/finish line.

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Crew chief: Like a head coach in football, the crew chief serves as the lead decisionmaker for the team. The crew chief works with engineers to determine strategy and decides on matters like whether to change two tires instead of four on pit stops.

Sticker tires: Tires with stickers on them, indicating they are new.

Scuff tires: Old tires that have enough tread to reuse if teams are out of sticker tires, but want to put fresher tires on cars.

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Outside and inside: At oval tracks like Iowa Speedway, "outside" means to the right, near the outer wall. "Inside" means to the left, closer to the inner wall.

Four-back, three-back, two-back, one-back: Spotters estimate the number of car lengths other drivers are behind their driver while communicating, usually saying "back" or "away" to communicate the number of car lengths a driver is behind.

Draft: A draft is an area of low pressure behind a car at speed, which pulls along any car closely following it, saving the second car fuel and driving effort. At short tracks like Iowa Speedway there's typically not a lot of conventional drafting.

Clean air versus dirty air: Clean air generally describes conditions at the front of the field, where cars handle better because there is little or no traffic in front of them. "Dirty air" is turbulence in traffic, which makes handling and passing more difficult.

Tight and loose: A car is "tight" when the front wheels lose traction before the rear wheels do, making the car harder to turn in the corners. Effectively the car wants to travel straight in the corners instead of turning. "Loose" is the opposite. The car's rear end steps out and makes it too easy to turn, causing handling issues.

Splitter: A flat device on the bottom front of the chassis which almost touches the ground. At speed, it produces downforce that helps balance the force on the front and rear of the car.

Spoiler: A metal, carbon or plastic strip on the rear of the car that provides downforce.

HANS device: A safety measure created after the death of driver Dale Earnhardt in a 2001 crash. At the time some drivers, including Earnhardt, were dying of basilar skull fractures caused when their heads hit their dashboards during crashes. The HANS — or Head and Neck Support Device — attaches to drivers' helmets and are anchored by securing them under the drivers' safety belts to keep the head stationary during impact.

Pole or pole position: The driver who has the best qualifying times generally wins the "pole," the most-preferred starting position, often the inside front spot.

Stop and go: A penalty that requires drivers to drive down pit road at the mandated non-race speed, stop in their pit and then exit pit road, again at non-race speed. A stop and go costs a driver valuable time.

Pass-through: A penalty which requires drivers to drive through pit road at non-race speed for violations like speeding on pit road.

Tail end of the longest line: A penalty that requires drivers to go to the end of the longest line on restarts.

Lap down: A driver who at least one lap behind the race leader. Drivers can be lapped if the leader passes them, putting them one lap or more behind.

Lucky dog and free pass: In NASCAR, the first driver one lap down gets a free pass. The driver may pass the pace car during a caution and get back on the lead lap.

Wave around: Lapped drivers can pass the leaders in front of them if the leaders make a pit stop under a caution flag. But they cannot pit under caution, which may put them under a disadvantage if their fuel is low or their tires are worn.

Overtime or "green, white, checkered": Overtime is NASCAR's way of trying to ensure races are completed under green-flag, or full race, conditions. If there is a caution in the final few laps, a race may be extended beyond its scheduled distance, with two laps under a green flag.

If the caution flag waves before the overtime leader takes the white flag, signifying the last lap, another overtime can be held. If the leader takes the white flag, the next flag ends the race.

"Blow up": Usually refers to mechanical failures that cause an engine critical damage.

Marbles: Throughout the race rubber comes off tires, often as small bits. Marbles are bits of rubber near the wall or on the inside of the track that drivers try to avoid because they makes handling worse.

Philip Joens covers retail and real estate for the Des Moines Register. He can be reached at 515-284-8184, pjoens@registermedia.com or on Twitter @Philip_Joens.

This article originally appeared on Des Moines Register: NASCAR vocabulary: What to know before Iowa Corn 350 at Iowa Speedway