A casino is an establishment for certain types of gambling. It can be a standalone building or part of a larger entertainment complex. Generally, casinos feature games of chance such as blackjack and roulette, with some having a skill element. Most casino games provide a predictable long-term advantage to the house, but some allow players to reduce that edge through proper play or by using strategies such as card counting. Those who successfully eliminate the house edge are known as advantage players.

Aside from gambling, some casinos are known for hosting live entertainment events such as concerts and sports. Some are also popular tourist attractions, drawing visitors from all over the world. In the United States, Las Vegas is the best-known casino city, while Atlantic City and Chicago have a smaller number of casinos but are still major gambling destinations. Several states have legalized casinos, and the number continues to grow as more people become interested in gambling.

Due to the large amounts of money handled within a casino, both patrons and staff may be tempted to cheat or steal, either in collusion or independently; most casinos have security measures in place to prevent this. In addition, casino employees are trained to recognize potential problems and respond quickly. Because of this, many casinos employ mathematicians and computer programmers specializing in gaming analysis to ensure their systems are fair. This work is usually done under strict confidentiality agreements. In some cases, these experts are independent contractors, and their work is not revealed to casino personnel.