Roulette is a casino game named after the French word meaning little wheel. In the game, players may choose to place bets on either a single number or a range of numbers, the colors red or black, or whether the number is odd or even, or if the numbers are high (19–36) or low (1–18).

To determine the winning number and color, a croupier spins a wheel in one direction, then spins a ball in the opposite direction around a tilted circular track running around the circumference of the wheel. The ball eventually loses momentum and falls onto the wheel and into one of 37 (in French/European roulette) or 38 (in American roulette) colored and numbered pockets on the wheel.