"Chapeau" is a French term signifying a hat or other covering for the head. In mainland European heraldry, it is used as a mark of ecclesiastical dignity, especially that of cardinals, which is called the red chapeau. It is worn over the shield by way of crest, as mitres and coronets are. Archbishops and patriarchs bore a green hat, with four rows of tassels; bishops wore the same color, but with three; abbots and apostolical prothonotaries with two.The chapeau is also sometimes used as a mark of secular dignity, such as a cap, or coronet armed with ermine, worn by dukes, etc.