Last name Ostr (Ost 
, Ostur 
, Ostr 
) , worldwide, is quite a common surname. The surname Ostr is habitual in Suriname, where it is quite a common surname, Belgium, where it is quite a rare surname, and Germany. In absolute terms, it most frequently occurs in Germany, the United States, and Brazil. Very seldom, Ostr is the forename as well as the last name.