Arcade, ahr kade', a series of arches supported by columns either attached to a wall or having an open space behind them. The word is used in contradistinction to colonnade, which is a series of columns supporting a straight entablature instead of arches. The arcade is found both in the inside and outside decoration of medieval buildings. In street architecture, it is a covered way or passage, either open at the side with a row of columns or entirely covered over and lined with shops and stalls. The finest arcades of this description are to be found in Paris, though Bologna, Padua and Berne also have fine examples.