Sieur

Sieur is an archaic French honorific meaning "sir" or "lord," used as a title for gentlemen and some nobles in medieval and early modern France. The term comes from Old French sieur, from Latin senior "older, elder." It was typically placed before a given name or used as "Le Sieur" in documents, similar to "the Sir" in English, and was used for knights, esquires, and men of rank who did not hold a formal feudal title of seigneur or count. It is distinct from "seigneur" (a feudal lord who held land under the crown) though both terms appear in historical records. In many sources, "sieur" functioned as a courtesy form of address rather than a formal rank.

As language evolved, the everyday address shifted to "monsieur" (from "mon sieur," my lord). By the 17th and 18th centuries, sieur fell out of common use in France, surviving mainly in legal texts, genealogical records, literary works, and some regional varieties. In the French-speaking colonies of North America, the form appears in records of the seigneurial system as part of the name or title of the landholder, e.g., Le Sieur [Name], reflecting its use as an honorific in formal naming rather than a fixed rank.

Today, sieur is regarded as archaic and is seldom used in modern standard French, except in historical writing or as a stylistic or genealogical reference. See also: monsieur, seigneur.