A casino is a building or room where people play gambling games. Unlike in other gambling establishments, where customers bet against each other, casino patrons play against the house. Most casino games have built in advantages that ensure the casino will win over the long term. The exact advantage is called the house edge, and it varies by game. In games such as poker where players bet against each other, the house takes a fee known as the rake.

Gambling probably predates recorded history, with primitive protodice and carved six-sided dice appearing in the earliest archaeological sites. However, the modern casino as a place where patrons could find a variety of ways to gamble under one roof did not emerge until the 16th century. During this time, a gambling craze swept Europe, and Italian aristocrats created private parties known as ridotti. This allowed them to gamble in a more intimate setting.

Casinos are generally highly secure places, with a combination of physical and electronic security measures. Most casinos use video cameras to monitor patrons and staff, while others employ chip tracking systems that allow them to monitor betting habits minute-by-minute. Many casinos also have specialized departments that oversee security, including a police force and a specialized surveillance department.

Casinos also enforce security by requiring that patrons keep their hands visible at all times and follow other expected behavior. This makes it much easier for security personnel to spot suspicious activity.