A casino (also called a gambling house or gaming hall) is an establishment for certain types of gambling. Casinos are often combined with hotels, restaurants, retail shops and other entertainment facilities. They also can be found on cruise ships and in some states that allow regulated commercial gambling, or on American Indian reservations.

The games played in casinos are based on chance, with some involving skill. The mathematically determined odds in casino games give the house an advantage over the players; this is known as the house edge or expected value. The casino makes money by taking a percentage of the wagers placed by patrons. In poker and other games where the casino takes a percentage of the pot, this is called the rake.

Because of the large amounts of money that are handled within a casino, both patrons and employees may be tempted to cheat or steal, either in collusion or independently. Therefore, casinos employ several security measures. Many casinos have video surveillance systems that cover the entire facility. Some have an eye-in-the-sky system that allows security personnel to monitor all tables, windows and doors simultaneously.

In the United States, the most famous casino is in Las Vegas, Nevada. It became a major tourist attraction in the 1950s when it was expanded to accommodate more slot machines and table games. Mobster funding helped to promote the casino, which gained a reputation for illegal activities and corrupt business practices. Legitimate businessmen were reluctant to invest in the casino industry because of its seamy image. However, the mobsters had ample cash from their drug dealing and extortion rackets, and they bought out or took over many of the newer casinos.