A casino is a public place where people can play games of chance. It may also offer food and drink, stage shows, dramatic scenery, or other forms of entertainment. It may be a part of a hotel or standalone building. The most famous casino is in Monte-Carlo, which opened in 1863 and has been a major source of income for the Principality of Monaco. Other well-known casinos are in Estoril, Portugal; Corfu, Greece; and Baden-Baden and Bad Homburg von der Hohe, Germany. In the United States, casino gambling is most prevalent in Las Vegas and Atlantic City. However, casino gambling has been expanding to other areas as well, including Indian reservations and in cities that are not subject to state anti-gambling laws.

Casinos earn their profits by collecting a percentage of the bets placed by patrons. The amount is a fraction of one percent or less for most games, but adds up to millions of dollars over time. Casinos also use comps, or free goods and services, to reward their biggest spenders. They may give them free hotel rooms, show tickets, meals, and even limo service or airline tickets.

Security in a casino includes many measures to prevent cheating by patrons or the staff. Many casinos have cameras that monitor the games and people. Some have catwalks over the gaming floor that allow surveillance personnel to look down through one-way glass at the table games and slot machines. Other casinos have specialized security officers for each game, watching for signs of palming, marking, or switching cards or dice.