A casino is a facility where people play games of chance for money. The games may include roulette, poker, blackjack, craps and keno, as well as slot machines and video poker. Most of these games have mathematically determined odds that give the house a small advantage over the players, allowing casinos to make billions of dollars in profits every year. This profit is known as the house edge. The casinos collect this edge from customers, either by charging them a commission called the rake or by simply subtracting it from their winnings.

While many casinos feature other forms of entertainment, such as musical shows and lighted fountains, the majority of their revenues come from gambling. In addition, the gambling industry is a huge employer in many states.

Casinos are usually staffed by workers whose primary responsibility is to supervise the gaming floor and monitor game rules and policies. Besides these traditional staff, modern casinos often employ sophisticated technological devices to ensure fairness of the games. These include “chip tracking,” which electronically records the amount of each bet minute-by-minute to detect tampering; and roulette wheels that are monitored regularly for statistical deviations from expected results.

In addition to these technology measures, casinos rely heavily on security personnel to keep their patrons safe. This starts on the gaming floors, where employees keep an eye on table games to spot any blatant cheating or tampering. More subtle signs of foul play, such as the way a dealer shuffles and deals cards or the pattern of betting at a particular table, are harder to miss.