A casino is a building where people can gamble and play games of chance. It might be an adult-oriented place with music and light shows, but it’s really about the gambling that brings in the money. Slot machines, blackjack, baccarat, roulette and other casino games generate the billions of dollars that make casinos profitable. 
The idea of a casino as a place to find a variety of ways to gamble under one roof probably didn’t start until the 16th century. That was when a gambling craze took hold in Europe, and Italian aristocrats used to gather at places called ridotti. 
Gambling in a casino requires an element of luck, but it also involves skill and knowledge. Casinos use mathematics to set odds and pay out winning bets. In games where players compete against each other, the house takes a small percentage of the total bets, known as the vig or rake.
In the United States, players must be 21 to gamble at a regulated casino. However, the minimum age for other forms of gambling varies by state and gambling product.