A casino is a facility where people can gamble by placing cash or chips on various events or outcomes, either randomly or with some element of skill. The game rules and payouts vary from casino to casino, but all have a built-in advantage for the house. Casinos also earn money by taking a percentage of the money wagered, known as the rake.

Depending on the game, the house advantage can be large or small. Those who possess sufficient skills to eliminate the long-term disadvantage are known as advantage players. Most games offer a predictable, long-term house advantage but some, such as blackjack and poker, have skill elements that can reduce the advantage.

Modern casinos employ many security measures to prevent theft and cheating by patrons or staff. These usually include a physical security force and a specialized surveillance department. The former patrols the premises and responds to calls for assistance or reports of suspicious activity; the latter monitors the entire facility using closed circuit television.

Casinos can be found all over the world, though most are concentrated in Las Vegas and Atlantic City. A number of American Indian tribes operate casinos on their reservations, which are not subject to state antigambling laws. In Europe, most countries changed their laws in the latter part of the 20th century to permit casino gambling. Some European casinos specialize in specific games, such as roulette and baccarat. Others have a more diverse range, including popular games like craps and poker.