A casino is a building or large room in which gambling activities take place. The term may also refer to a group of such rooms. The room is usually staffed to supervise and control gambling. Casinos are often located near or combined with hotels, restaurants, retail shops and other tourist attractions. In the United States, casinos are legal in some states and are very popular with tourists and locals.
The games in a casino are usually based on chance, although some have an element of skill. The house has a mathematical advantage over the players, which can be expressed as an expected value that is uniformly negative (from the player’s point of view). This is called the “house edge” or the “expected value”. In games such as blackjack and video poker, the odds are adjusted to ensure that the casino makes a profit. In a game such as poker where patrons play against each other, the casino makes its profit by taking a percentage of each pot or charging an hourly fee.
Because of the large amount of money handled within a casino, both patrons and staff may be tempted to cheat or steal, either in collusion or independently. To prevent this, most casinos have extensive security measures. These include a high-tech “eye-in-the-sky” surveillance system that can monitor the entire casino floor at once and that can be focused on specific suspicious patrons by security workers in a separate room filled with banks of monitors.