A casino is a building or room used for social amusements, especially gambling. Casinos generate billions of dollars each year for the owners, corporations, investors, and Native American tribes that operate them. They also bring in revenue for state and local governments through taxes and fees. In addition to their financial profits, casinos provide employment opportunities and attract tourists.

A majority of casino gambling involves games of chance, although some have an element of skill. Casinos employ mathematicians and computer programmers to determine the long-term house edge of each game and its statistical variance, which is a measure of randomness. These figures help casino managers to predict how much money they will lose over time and make adjustments accordingly. Players who can eliminate the inherent long-term disadvantage of a game are called advantage players.

In 2004, the number of commercial casinos in the United States reached fifty-seven, with twenty-eight states permitting tribal gaming and eight states authorizing racetrack casinos. These are often built at or near horse racing tracks and feature table games, slot machines, and video poker. In addition to traditional casinos, some Native American tribes have remodeled their bingo halls into full-scale casinos.

When most people think of a casino, they envision one of the enormous megaresorts in Las Vegas, complete with glitzy hotels, fun and games, and nonstop entertainment. But many casinos are much smaller establishments, defined more by their types of gambling than by glitz and glamour.