Nielsen
A classic Danish and North German patronymic meaning “son of Niels.”
The #810 most common surname in the United States (2010 Census) — about 1 in every 7,218 Americans shares it.
Etymology
Nielsen is a patronymic surname built from the given name Niels plus the suffix -sen, meaning “son of.” Niels is the Danish form of Nicholas, ultimately from Greek Nikolaos, “victory of the people.” So the name literally means “son of Niels.”
History
The surname is especially common in Denmark and also appears in northern Germany and other Scandinavian-linked communities. Nineteenth-century writers often grouped it with other Scandinavian -son/-sen patronymics and sometimes discussed it alongside English Nelson or Scottish Neilson. In modern use it remains one of the best-known Danish surnames.
Origin
Regions
Variant spellings
Fun fact
In Danish naming, -sen surnames like Nielsen became fixed family names earlier than in some other Scandinavian regions, which is one reason they are so widespread today.
From the historical record
“names) is in Holland proper Janzon or Jantzon. The family of the German scholar Mommsen came from the former Danish province of Schleswig. The Danish Nielsen has been wrongly equated by some Continental writers with the Dutch Cornelissen. The (High) German -sohn (as in Mendelssohn, Davidsohn, etc.) is, however…”
— Surnames of the United Kingdom: a concise etymological dictionary (2 vols in 1)