Roulette is a casino gambling game named after a French word meaning "small wheel". In the game a wheel is spun in one direction, then a ball spins in the opposite direction around a tilted circular surface running around the circumference of the wheel. The ball eventually falls onto the wheel and into one of 38 colored and numbered pockets.
The main pockets are numbered from 1 to 36 alternating between red and black, but the pockets are not in numerical order around the wheel, and there are instances of consecutive numbers being the same color. There are green pockets numbered 0 and 00.
Players can place 'inside' bets (selecting the number of the pocket the ball will land in, or range of pockets based on their position), and 'outside' bets (including bets on various positional groupings of pockets, pocket colors, or whether it is odd or even). The payout odds for each type of bet is based on its probability.