When most people think of casinos, they envision the neon-lit megaresorts of Las Vegas. But the term casino has a more precise meaning: a building or large room that is equipped for social amusements, especially gambling.

In the United States, the casino industry is massive, generating billions of dollars each year for the companies, investors, and Native American tribes that own and operate them. State and local governments also reap profits from casinos in the form of taxes and fees.

The economic backbone of most casinos is the use of slot machines and video poker machines. These devices generate high volumes of play at relatively small stakes, allowing casinos to adjust machine odds to their advantage. Casinos hire mathematicians to calculate the house edge and variance for each game they offer.

To attract and retain customers, casinos use a variety of tricks. They offer patrons comp programs that tally up points they can exchange for free meals, drinks, and shows. They decorate with bright colors like red, which is thought to stimulate the senses and make people lose track of time. They don’t display clocks because people would see them as a reminder to stop gambling and leave.

Gambling addiction is a serious problem, and the number of addicted gamblers is rising. In addition, the proliferation of new casinos in recent years is straining local governments’ ability to provide needed services, such as public education and law enforcement. Many communities are calling for a rethinking of the way casinos are run and regulated.