A casino is an entertainment venue that makes the bulk of its money by gambling. While the glitz of musical shows, lighted fountains, shopping centers and hotel rooms adds to the appeal, casinos would not exist without games of chance like slot machines, blackjack, roulette, craps and keno. These games generate the billions in profits that U.S. casinos rake in every year.

The term casino was first used to refer to a public hall for music and dancing; by the second half of the 19th century it had come to be applied to a specific group of gaming rooms. Casinos have become a worldwide phenomenon, and are now almost universally accepted as places for people to gamble.

Many of the largest casinos are in Las Vegas, which accounts for about a fifth of all casino revenue in the United States. The next most profitable are Atlantic City, New Jersey and Chicago.

Casinos are often regulated by state laws that require them to display signs warning patrons of the dangers of gambling, and to provide contact information for responsible gambling organizations. Most states also include statutory funding for these organizations as a condition of casino licensing.

Most casinos have strict security measures, because they deal with large amounts of currency. Employees keep close watch on patrons to make sure that no one is cheating or stealing. In addition, the tables are watched by pit bosses and table managers who can spot betting patterns that might indicate collusion or other forms of cheating. Finally, elaborate surveillance systems allow casino workers to monitor the entire casino at once from a room filled with banks of cameras.