Casino is a gambling establishment offering a wide range of games of chance and some with an element of skill. Generally, these games give the house an inherent long-term disadvantage to players that is mathematically predictable and is known as the house edge (or vigorish). Players possessing sufficient skills to eliminate this advantage are known as advantage players. The house edge for card games such as blackjack is mathematically calculated as the percentage of the total bets that will be lost to the house over a given number of hands played with optimal strategy.

Casinos are legal in most countries, and many are highly profitable. In addition to gambling, casinos sometimes offer restaurants, retail shops, and live entertainment. They are usually built near or combined with hotels, resorts, and other tourist attractions. In some cases, the owners of the casinos also operate other tourist facilities, such as theme parks or racetracks.

A modern casino uses technology extensively, especially in security and game supervision. For example, chips with built-in microcircuitry allow casinos to oversee the amount wagered on a game minute by minute; roulette wheels are electronically monitored to discover any deviation from their expected results. Casinos also use computers to automate some games, such as blackjack and video poker.

Casinos are a significant source of income for some governments, and are regulated by law in many jurisdictions. There are also a number of private, commercial casinos operated by major hotel chains, and by independent operators in places such as Macau, which was a Portuguese colony until 1999.