A casino, or casin, is a public room where gambling games are played. The games played in a casino may differ, but all have the same basic structure: players place bets on the outcome of a game or series of games, and the casino takes a percentage of all bets made. Casinos can also offer food and drink, and may feature entertainment performances, such as a show or a musical act. In some jurisdictions, casinos are operated by government-sponsored enterprises, and patrons must be a certain age to gamble.

In many cities, the casino business is booming. New Jersey, for instance, has seen a recent rise in the number of new gambling establishments, while Las Vegas continues to be one of the most popular destinations for visitors from around the world. Among the most impressive casino buildings in the world is the Venetian Resort in Macau, which boasts an incredible 376,000 square feet of gaming space and more than 640 tables.

Gambling in its various forms has been a popular pastime for millennia. It is believed that some form of gambling existed as early as Mesopotamia, and was prevalent throughout ancient Greece, the Roman Empire, and medieval Europe. The modern casinos owe their growth to changing laws and increased social acceptance of gambling.

The games that a casino offers are usually divided into three categories: gaming machines, table games, and random number games. Gaming machines allow multiple players to compete against each other without the intervention of croupiers or dealers, while table games require the involvement of trained personnel. Random number games, including roulette and dice, are overseen by computer systems that monitor bets minute by minute and alert casinos to any statistical deviations from their expected results.