A casino, also known as a gambling hall or a gaming house, is a building or room where people can gamble on games of chance or skill. The precise origin of gambling is unknown, but it has long been a part of human culture. The modern casino has three general categories of game: gaming machines, table games, and random number games. Gaming machines are operated by computer programs or mechanical devices and are typically fixed with predetermined odds that the player cannot beat. Table games involve one or more players competing against the house and are run by croupiers. Random number games are based on the selection of numbers or symbols that correspond to winning combinations.

In the 21st century, most casinos are operated as private enterprises with their profits made from the admission of patrons and the sale of food, drinks, and merchandise. In some cases, these businesses are combined with hotels or other tourist attractions, and some are located aboard cruise ships. The largest casino in the world is located in Las Vegas, Nevada, with an estimated revenue of US$4.2 billion.

A casino is a place where wealthy men and women gather to gamble. Among the most famous is the Casino de Monte-Carlo in Monaco, which opened in 1863 and remains a symbol of luxury and elite leisure. There are many other examples of casinos throughout the world, but these are generally less well-known than Monte Carlo.