A casino (or gambling house) is an establishment that allows customers to gamble by playing games of chance or skill. It may also be a place where entertainment, such as stand-up comedy or concerts, is presented. The precise origin of gambling is unknown, but it has been practiced in many societies throughout history. Modern casinos are often combined with hotels, restaurants and/or retail shops. Some are located in tourist areas. In the United States, there are more than 1,000 casinos.
Many casinos offer a wide variety of games, such as blackjack, craps, roulette, and video poker. The games are usually operated by a dealer and are played against other players or the house. Most of these games have mathematically determined odds that give the house a consistent advantage over the players. The advantage is known as the house edge. In games such as poker where players play against each other, the house takes a percentage of the pot, called the rake.
Due to the large amounts of money handled within casinos, both patrons and employees may be tempted to cheat or steal, either in collusion with each other or independently. To counter this, most casinos have security measures in place. These usually include a physical security force and a specialized surveillance department. Some casinos also use catwalks over the gaming floor, allowing security personnel to look directly down at the activities on the tables and slots through one-way glass. This is an attempt to deter cheating and stealing by making it more difficult for people to hide their actions from casino surveillance.