Surname Dumiak (Dumiak 
, Думяк 
) , all over the world, is a rare family name. The cognomen Dumiak is habitual in Ukraine, where it is a rare surname, Kazakhstan, where it is a very rare surname, and Russia. In absolute terms, it is the most numerous in Ukraine, the United States, and Russia. Much less frequently, Dumiak is the forename as well as the last name.