A casino is a large, specially designed place where people can play gambling games. Most casino games have a certain element of skill, such as poker or blackjack, but they are mainly games of chance. The house always has a mathematical advantage in these games, and this advantage is known as the house edge. Casinos make money by charging a fee to gamblers and giving them complimentary items, called comps. They also take a percentage of winnings, or rakes, from players.

Modern casinos are highly sophisticated and use a variety of tricks to attract and keep customers. The atmosphere is designed around noise, light, and excitement; a typical casino features a maze of slot machines and tables, with the sounds of clanging coins and bells. Windows are rare, and chimes are not heard; the absence of windows and clocks allows patrons to lose track of time and continue gambling for hours without realizing how much money they have lost.

Casinos have become increasingly technological in the 1990s. In addition to video cameras that monitor patrons for security purposes, they have a wide range of automated systems that oversee individual games. For example, chips with built-in microcircuitry interact with electronic systems that record the exact amount of money wagered minute by minute; roulette wheels are electronically monitored to discover any statistical deviation from expected results.

Most casinos cater to high rollers, who spend tens of thousands of dollars on average. To encourage them to spend more, they are given perks such as free luxury suites and lavish personal attention. Comps are also offered to smaller gamblers.