A casino, sometimes spelled casin or casiono, is an establishment where people can gamble and play games of chance. These establishments may also include restaurants, bars and stage shows. In the United States, they are often combined with hotels and vacation resorts.

In casinos, customers bet against the house, with games of chance such as roulette, craps, baccarat and blackjack. Some of these games require skill, such as poker, but most do not. Most casinos earn a large proportion of their revenue from slot machines, where players insert coins and push buttons to watch varying bands of colored shapes roll on reels (either physical or video). A player who hits the right combination wins a predetermined amount of money.

Gambling has been popular throughout history, from ancient Mesopotamia to Elizabethan England and Napoleon’s France. In modern times, gambling is widespread and has become a major industry worldwide.

During the 1950s, organized crime figures poured mob money into Reno and Las Vegas. They took sole or partial ownership of many casinos and influenced the results of games by using threats to intimidate the staff. As mob influence faded, legitimate businessmen jumped into the casino business with deep pockets. The Hilton hotel chain and real estate developers became especially successful at removing the taint of gangster involvement. Other businesses have moved in to capitalize on the gambling industry, including airlines and cruise lines. Casinos are now found in most states and internationally, and some American Indian reservations are licensed to operate them as well.