A casino, also known as a gambling house or gaming house, is a building or online site where people can perform acts of gambling. Casinos are owned and operated by private companies or public entities and may be located in states where gambling is legal. Most casinos offer a variety of games, such as blackjack, poker, and roulette. Some also offer sports betting and horse racing.

Although some people visit casinos solely to gamble, others go to watch live entertainment or simply to socialize. In addition to having numerous casino games, many casinos have restaurants and bars, as well as other amenities such as spas and gyms. Some even have pools and dance clubs. In the United States, Las Vegas has the largest number of casinos, followed by Atlantic City and Chicago.

While there is no way to guarantee that a person will win at any given casino game, the odds are in favor of the house, which makes money from the money played by patrons. Because of this, casinos make significant investments in order to attract and keep patrons, including testing various color schemes, sounds, and scents to determine which are most appealing.

Due to the large amounts of money that are handled within a casino, both patrons and staff can be tempted to steal or cheat, either in collusion or independently. Because of this, most modern casinos have security measures in place to prevent such activities. These usually include a physical security force and a specialized surveillance department.