Cognomen רוסן (Rossen 
, רוסן 
) , in the entire world, is quite a rare last name. The cognomen רוסן is habitual in Denmark, where it is quite a common surname, Netherlands, where it is quite a rare surname, and Belgium. Measured by absolute frequency, it is the most numerous in Netherlands, Denmark, and the United States. Much less frequently, רוסן is the forename as well as the last name.