A casino, also known as a gaming house, is a facility where various gambling activities are conducted. Its customers gamble by playing games of chance, in some cases augmented by an element of skill, such as poker, blackjack and video poker. The games usually have mathematically determined odds that ensure the house always has a slight advantage over the players (this can be more precisely expressed by the notion of expected value). The profits earned by the casino from these games are called the vig or rake. The house also may give out complimentary items or comps to gamblers.

Casinos are often designed around noise, light and excitement to attract patrons and encourage them to gamble. Slot machines are commonly accompanied by electronic sounds, bells, whistles and clangs to simulate the sound of coins dropping. Casinos also feature tables for card and table games such as craps, roulette, baccarat and poker. Some casinos offer restaurants and bars, and some even host shows and other events.

The casino industry is a major source of revenue for many governments. It is estimated that worldwide annual revenue from casino gambling exceeds US$50 billion, and it is growing rapidly. In addition to traditional land-based casinos, the industry has expanded to include online and mobile gambling. The legality of online casinos varies by jurisdiction. Some states have banned them, while others endorse them and regulate them. Others allow only certain types of online casinos, such as those operated by Indian tribes.