Saturday, November 03, 2012
Found primarily in France, New France (French-Canada, Louisiana, etc.), and Scotland, dit names are essentially an alias tacked on to a family name or surname. Dit in French is a form of the word dire, which means "to say," and in the case of dit names is translated loosely as "that is to say," or "called." Therefore, the first name is the family's original surname, passed down to them by an ancestor, while the "dit" name is the name the person/family is actually called or known as. Dit names are used by families, not specific individuals, and are usually passed down to future generations, either in place of the orginal surname, or in addition to it.
Why a dit name? Dit names were often adopted by families to distinguish them from another branch of the same family. Interestingly, many dit names derived from military service, where early French military rules required a nom de guerre, or nickname, for all regular soldiers. The specific dit name may have been chosen for many of the same reasons as the original surname - as a nickname based on trade or physical characteristics, to identify the ancestral place of origin (Andre Jarret de Beauregard, where Beauregard refers to the ancestral home in the French province of Dauphine), etc.
A dit name can be legally used to replace the family's original surname, so you may find an individual listed with a dit name, or under either the original surname or the dit name. Dit names may also be found reversed with the original surname, or as hyphenated surnames.
Hudon dit Beaulieu
Beaulieu dit Hudon
When recording a dit name in your family tree software, it is generally standard practice to record it in its most common form - e.g. Hudon dit Beaulieu. A standardized list of dit names with their common variants can be found in Rene Jette's Répertoire des Noms de Famille du Québec" des Origines à 1825 and Msgr Cyprien Tanguay's Dictionnaire genealogique des familles canadiennes (Volume 7). Another extensive source is The dit Name: French Canadian Surnames, Aliases, Adulterations, and Anglicizations by Robert J. Quentin. When the name is not found in one of the above sources, you can use a phone book (Québec City or Montréal) to select the most common form, or just record it in the form most often used by your ancestors.
Info found on About.com genealogy