Carreau is derived from the French word for "bolt", specifically that of either a crossbow or a catapult. It is also the name of the "Diamond" playing card suit.
In Admirable History by Father Sebastien Michaelis, Carreau is the name of a demon mentioned under the second hierarchy of the book. He is reputed to be the prince of Powers, where he tempts men with hardness of heart. Carreau is opposed by St. Vincent Ferrer.