A casino is a gambling house or establishment that offers a variety of games of chance. Its precise origin is unknown, but it is believed that some form of gambling has existed since prehistoric times, with primitive protodice (cut knuckle bones) and carved six-sided dice appearing at archaeological sites. Modern casinos offer an enormous range of games, with a variety of rules and etiquette.

Casinos are regulated by governments in some countries, and operate in others on Native American reservations, where they can avoid state antigambling laws. The United States has several regulated casinos, including the Atlantic City and Las Vegas. Casinos are also popular in Europe, where they were introduced during the second half of the 20th century and quickly became a tourist attraction.

The term casino is also used for private clubs that cater to high rollers, such as those on the French Riviera. These clubs often have lofty gold-trimmed ceilings and are filled with chandeliers. Patrons are expected to dress in formal attire, and service is excellent.

The casino is a major source of income for many hotels, and is one reason why resorts compete to be the largest in their region or even the world. But the industry faces many challenges, especially with compulsive gamblers. Studies suggest that the costs of treating them and the loss in productivity from their addictions more than offset any economic benefits from a casino. Nevertheless, the casino remains an important source of entertainment for millions of people.