A casino is an establishment for certain types of gambling. Modern casinos often include a hotel, restaurants, retail shops, and entertainment venues. They may also contain arcade games or other forms of gambling in addition to slot machines and black jack. The exact origin of gambling is unknown, but it has been popular throughout history in nearly every society. In some countries, casinos are operated by the government, while in others they are private businesses. Some of the largest and most famous casinos in the world are located in Las Vegas, Nevada, and Atlantic City, New Jersey.

Most casino games have an inherent long-term advantage for the house, which is called the house edge or vigorish. However, some casino games have a skill element, and players with sufficient skills can reduce this advantage or even eliminate it entirely. Such skilled players are known as advantage players.

Because large amounts of money are handled within a casino, both patrons and staff may be tempted to cheat or steal, in collusion with each other or independently. To counter this, most casinos have a variety of security measures. These may include video surveillance, security cameras, and random checks of player cards. Many casinos also employ specially trained security personnel to monitor the games and players. Technology has also dramatically increased the capabilities of casino security, especially in the 1990s. For example, betting chips with built-in microcircuitry enable casinos to oversee the amount wagered on a game minute by minute, and roulette wheels are electronically monitored regularly to discover quickly any statistical deviation from their expected results.