Janssen (surname)

Janssen is a common Dutch and North German patronymic surname. It means "son of Jan" or "son of John." Jan is a Dutch and North German form of the name John, derived from the Hebrew name Yochanan, meaning "God is gracious."

The surname Janssen, like many patronymic surnames, originated during the Middle Ages as a way to identify individuals based on their father's given name. The practice of adding a suffix such as "-sen" or "-son" to a father's name was widespread in Germanic-speaking regions.

Because "Jan" was a popular given name, the surname Janssen evolved independently in multiple locations, leading to various families with the same surname who are not necessarily related. Spelling variations of the name include Jansen, Jansens, Janson, and Janszen.

Distribution of the name is primarily found in the Netherlands, Belgium, Germany, and regions with significant Dutch or German diaspora populations, such as the United States, Canada, Australia, and South Africa.

Famous people with the surname Janssen include:

• Famke Janssen: A Dutch actress and former fashion model.
• Zacharias Janssen: An early microscope maker, often credited (along with his father, Hans Martens) with inventing the first microscope.
• Pierre Jules César Janssen: A French astronomer.

The surname Janssen reflects a history of family lineage and the common practice of patronymic naming conventions in Germanic cultures.