A casino is a place where people can gamble money in games of chance. Most games have some element of skill, but casinos earn their money by taking a commission on wagers, which is known as the house edge or vig (vigorish). Casinos also offer complimentary items to players and may give them loyalty points that can be exchanged for cash.

The precise origin of gambling is unknown, but it appears in nearly every culture throughout history. Ancient Mesopotamia, Egypt and Greece all had gambling. In modern times, it has been popular in the United States and most of Europe, but is rarer in Asia. In many countries, gambling is legalized and regulated.

Casinos use a variety of security measures to protect their patrons and property. The first line of defense is human security personnel on the floor of the casino, watching for blatant cheating such as palming cards or marking or switching dice. Pit bosses and table managers watch over tables with a broader view, checking to see if patrons are stealing from each other or following betting patterns that could indicate cheating.

The interior design of a casino is designed to convey an air of luxury and excitement, with plush carpeting and carefully chosen lighting. Some casinos also display a large prize, such as a sports car, to draw attention and add drama. In the past, mobster money helped spawn casinos in Reno and Las Vegas, but this often came with a taint of illegal rackets.