Bruun is a surname of North Germanic origin. The meaning is brown (brun in Danish, Swedish and Norwegian). In Denmark, the name is known to have been in use since the 13th century in the form Bruun. Other spelling variants are Bruhn and Brun. Today, c. 0.1% of the population carries Bruun as their surname or middle name. The name is also in use in Norway (c. 0.02% of the population), the Faroe Islands and the other Nordic countries (even less frequent). In the Danish translation of Peanuts, Charlie Brown is called Søren Brun. Abundance.
https://en.wikipedia.org/wiki/Bruun