A casino is a gambling establishment where patrons can gamble on games of chance or skill. Some casinos also offer food and drinks, and some even host live entertainment. Casinos are most often located in cities with large populations and a history of gambling, such as Las Vegas, Reno, and Atlantic City. Most states have laws regulating the operation of casinos.

Although gambling probably predates written history, with primitive prototype dice and carved six-sided knuckle bones found in archaeological sites, the modern casino as an institution did not emerge until the 16th century. At that time, a gambling craze swept Europe, and Italian nobles used their country houses, known as ridotti, to hold private parties where they could play a variety of games. The word casino probably derived from these parties, as the houses were not licensed or sanctioned by religious or legal authorities.

Modern casinos feature a wide variety of games, from classic table games like blackjack and roulette to slot machines and poker rooms. They are decorated in bright colors to stimulate the senses of sight and sound, with bells, whistles, and clangs constantly reminding patrons to place their bets. More than 15,000 miles of neon tubing is used to light the casinos on the Las Vegas Strip. Red is a color that is especially effective at attracting attention; it also makes players lose track of time, which is why there are seldom clocks in a casino.

Due to the huge amounts of money handled, a casino must take precautions against cheating and theft by patrons and employees. Security measures include cameras and other technological devices. Casinos also reward loyal patrons with free goods and services, called comps, based on the amount of money they spend at the establishment.