The game of Roullete roo-lay-t (French: “little wheel”) is a casino game in which a small ball rolls around a spinning wheel and people bet on what number it will land on. The payout odds are based on the probability of each bet. Players can choose to place bets on a single number, various groupings of numbers, whether the color red or black, odd or even, or if the numbers are high (19-36) or low (1-18). The house edge for all bets is 5.26% unless otherwise stated.

The roulette wheel consists of a solid, slightly convex wooden disk with a grooved surface and thirty-six compartments painted alternately in red and black, with the exception of two green pockets on American-style wheels that carry the marks 0 and 00. The compartments are separated by metal partitions called frets, or canoes by roulette croupiers, and each one is marked with a number nonconsecutively from 1 to 36. Traditionally, the compartments were colored either red or black, but since 1838 green has been used for the zeros. Red and black still appear on some modern French-style wheels. Historically, the game of roulette was played in gambling dens and casinos where cheating devices could be hidden.