A casino is an establishment where people can gamble by playing games of chance, or in some cases a game with an element of skill. Slot machines, poker, blackjack, craps and roulette are all examples of casino games. Casinos make money by charging a commission on winning bets, known as the house edge, or by taking a percentage of each bet played, known as rake. Casinos also earn revenue from complimentary goods, or comps, given to players.

Although some casinos are purely gambling establishments, others provide a wide variety of entertainment and leisure activities in addition to gambling. They may feature musical shows, lighted fountains, shopping centers and even hotel rooms. They are most often located in cities with large populations, such as Las Vegas, Atlantic City and Macau. Casinos are also found on American Indian reservations and in other states where gambling is legal.

Gambling is a popular activity that is practiced in almost every society around the world. The precise origin of gambling is unknown, but it has been found in nearly all cultures and civilizations. It has been a part of human culture since at least ancient times, when it was recorded in writing. Modern casino games are based on mathematical odds, which give the house an advantage over patrons. These advantages may be small — lower than two percent in the case of blackjack, for example — but their cumulative effect makes them profitable over time.