A casino is a gambling establishment that offers players the chance to gamble money or other goods on games of chance or skill. Casinos earn billions of dollars each year from customers who risk money in games of chance or skill. They pay out winnings to customers and use the remaining money to cover operating expenses. Some casinos also offer free drinks, food and other amenities to lure customers. Casinos vary in size and scope, from massive resorts to small card rooms. Many casinos are operated by governmental agencies or Native American tribes. Others are owned by private corporations or investors.

While there are no hard figures on the number of people who visit casinos each year, it is clear that they are very popular. In the United States, for example, a quarter of all adults over 21 visited a casino in 2002. These casinos bring in billions of dollars for the companies, investors and local governments that own and operate them.

The largest casinos in the world can be found in cities such as Las Vegas, Macau and Foxwoods. These enormous complexes often feature restaurants and other amenities such as shopping and golfing, as well as thousands of slot machines and table games.

Casinos have a built in advantage over customers that is mathematically determined and is called the house edge. This is a tiny percentage, lower than two percent, but it adds up over the millions of bets placed each day. Some casino patrons learn advanced strategy, such as counting cards in blackjack, which can shift the house edge slightly in their favor.