Dreyfuss is a surname usually found among Jews from the Rhine valley in modern day Germany and Alsace (France). In German language, drei Fuß means three feet, referring to a three-legged stool or tripod.
The commonly accepted place of origin is the German city of Trier. The Latin name for the city was "Treveris," which developed into its current pronunciation through sound shifts of /t/>/d/ and /f/>/v/. The spelling variants tend to correspond to the country the family was living in at the time the spelling was standardized. The use of one "s" tends to be more common among people of French origin, while the use of two "s" tends to be found among those of German descent (stemming from the use of the long s (ſ) and ß (s sharp).
Another possible origin of the surname is the French city of Troyes in Champagne, the pronunciation of Troyes meaning "three" in French as does "Drey" in German. Troyes, birthplace of the famous medieval Jewish scholar Rashi was an important medieval center of Judaism. As Jews were repeatedly expelled from France between 1182 and 1394, they migrated eastwards and settled in the Rhine valley, becoming known as Ashkenazi Jews. The Rhine valley was within the (Germanic) Holy Roman Empire, but Elsaß/Alsace and Lothringen/Lorraine was taken over by France since the late 17th century.
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