A casino is a gambling establishment where people play games of chance for money. It is also a facility where people can place bets on sports events and other activities. Various forms of legalized casino gambling have been popular throughout history in many cultures and societies, including ancient Mesopotamia, China, Greece, Roman Egypt and Elizabethan England. In modern times casinos have become a major form of entertainment, providing jobs and tax revenue in some communities.

A key aspect of any casino is security. Because of the large amount of money involved, patrons and employees may be tempted to cheat or steal. This is why most casinos employ a wide range of security measures. For example, all casino chips are printed with a unique serial number and have a microcircuit that allows them to be tracked minute-by-minute; roulette wheels are electronically monitored to detect any statistical deviation from their expected results; and the shuffles, dealing and betting patterns of table games are supervised for irregularities.

Casinos earn their profits by taking a percentage of all bets placed. This is known as the house edge, and it can vary by game. Some casinos, such as those in Las Vegas, have a high house edge, while others, such as those on American Indian reservations, have low ones. The house edge can be reduced by skillful play, which is known as advantage gaming.