An arcade is a set of arches that is placed side by side. Do not confuse this with a tunnel (or barrel) vault, which is a set of arches placed front to back. The triumphal arch can be a specific type of arcade. In ancient Rome arcades were places where food and entertainments were dispensed, somewhat like a booth. Because games were played in these, later uses of the term arcade were places to play games - think Cedar Point. It is also from this idea that video arcade games also got the name.