Last name Ідельсон (Idelsohn 
, Ідельсон 
) , globally, is a very rare cognomen. The last name Ідельсон is habitual in Argentina, where it is a very rare surname, Spain, where it is an extremely rare surname, and Ukraine. In absolute terms, it is commonest in Argentina, Brazil, and the United States. Much less frequently, Ідельсон is the forename as well as the last name.