Guillou

Guillou is a surname of French origin. It is a relatively common surname, primarily found in Brittany, France. The name is derived from the Breton given name "Gwilhou," which is a form of "William." Therefore, Guillou essentially means "son of William" or "descendant of William."

The name has also spread beyond France due to migration and emigration. Notable people with the surname Guillou include:

• Jan Guillou: A Swedish author and journalist.

The spelling variations of the name might include Guilloux or similar forms, depending on regional variations and historical evolution of French orthography.

As a surname, its primary significance lies in its genealogical and historical connections to individuals and families bearing the name and its origins in Breton/French culture.