A casino is an establishment for certain types of gambling. In the most general sense, a casino is a building or room where people can gamble, but it is also possible for a casino to be an entire complex built to accommodate gambling. Many casinos are combined with hotels, restaurants, retail shops, cruise ships or other tourist attractions. The term can also refer to the gaming rooms in some military and non-military usage.

A successful casino makes billions of dollars each year for the companies, investors, and Native American tribes that own and operate them. In turn, those casinos provide jobs and tax revenues for local governments. While casino patrons may be tempted to cheat or steal, in collusion or independently, security departments are often able to prevent such actions through the use of cameras and other technological measures.

Gambling has been a part of human culture for millennia, with evidence dating back to 2300 BC in China. It was not until the mid-twentieth century that it became a legal enterprise in America, and even then only in a few states. The success of casino gambling is largely dependent upon attracting and keeping customers, which requires enormous marketing efforts and large capital investments in facilities, games, and employees. Casinos go to great lengths to determine what colors, sounds, and scents appeal to their target market in order to maximize revenue.