A casino is a building or room where gambling takes place. It can also refer to a group of buildings or rooms that are connected by a common entrance and have similar features, such as a gaming floor. Casinos are a major source of revenue in many countries, and are often considered to be entertainment centers. They may feature music, light shows, and other forms of entertainment, as well as restaurants and shopping. Some casinos are operated by government agencies or Native American tribes. Others are owned by private corporations or investors. The most successful casinos make billions in profits each year, and attract millions of tourists annually.

The games played in a casino are usually based on chance. Slot machines, blackjack, poker, roulette, craps, and baccarat are the most popular casino games. Other games, such as keno, bingo, and gambling on sporting or racing events, are less popular. Casinos often offer complimentary goods or services to their most frequent and high-stakes players, such as free hotel rooms, meals, tickets to shows, and reduced-fare transportation.

Because large amounts of money are handled within a casino, patrons and staff may be tempted to cheat or steal. To protect their assets, casinos employ a variety of security measures. These include video surveillance, security guards, and rules of conduct. In addition, some casinos use technology to monitor the games themselves; for example, chips with built-in microcircuitry interact with electronic systems on table games to record the amount wagered minute by minute, and automated roulette wheels are monitored regularly to detect any statistical deviation from their expected results.