1911 Encyclopædia Britannica/Monsieur

MONSIEUR (Fr., formed from mon, my, and sieur, lord), the general title of address in France used vocatively in speaking formally to any male person, like the English "sir" or prefixed to the name like the English "Mr." It is, however, in France also prefixed to nobiliary, official, and other titles, e.g. Monsieur le president, Monsieur le duc d'E., &c. It is abbreviated M., not Mons. As a specific title "Monsieur" (tout court) was used from the time of Louis XIV. of the eldest brother of the king, as "Monseigneur" was of the dauphin; as a general title of address it was given to the princely members of a royal house.