Family name קוסר (Kooser 
, קוסר 
) , all around the world, is a rare last name. The cognomen קוסר is habitual in Estonia, where it is quite a rare surname, the United States, where it is a rare surname, and Israel, where it is a very rare surname. In absolute terms, this name is the most popular in the United States, Estonia, and India. Much less frequently, קוסר is the forename as well as the last name.