Roulette, or Roullete, is a casino game in which players place bets on the outcome of a spin of a wheel. Bets may be placed on a single number, various groupings of numbers, the colors red or black, whether the number is odd or even, and other options. The game of roulette emerged in the 18th century in Europe, and has since become a popular casino game. It is one of the few gambling games that allow bets to be made without the house taking a percentage of the total stake.

When a player places a bet, they place their chips on a betting mat, with the precise placement of each chip indicating the type of bet being made. The dealer then announces “no more bets!” to close the betting for that round. The winning bets are then paid, and the table is cleared for play on the next spin.

The Roulette wheel consists of a solid, slightly convex disk with compartments that revolve around it. Thirty-six of these are painted alternately red and black and numbered 1 to 36; on European wheels there is an additional green division numbered 0.

When the ball drops into one of these compartments, it halts in the last section of the wheel’s track and comes to rest against a wall or other obstruction. A croupier then sweeps the wheel and rakes the table to collect bets and payouts.

As the game spread across the world, casinos introduced a variety of measures to combat cheating by both gamblers and dealers. These included putting the wheel on top of the table, placing it on an elevated pedestal and making the betting area simpler. A specialized roulette table was also developed, with the numbers on the wheel and on the betting mat arranged in a more random pattern than on a standard table.

In addition, the materials used to make the balls have been changed. While most are still ivorine, other types of synthetic materials are now employed. These materials have an effect on the game because a small, light ceramic ball requires more revolutions of the wheel track to come to rest than a larger, heavier ivorine ball would.