Surname Khayn (Khayn 
, Хаин 
, Хайн 
) , across the world, is a rare cognomen. The cognomen Khayn is habitual in Russia, where it is a rare surname, Ukraine, where it is a very rare surname, and the United States, where it is an extremely rare surname. In absolute terms, the name is most common in Russia, India, and Ukraine. Very seldom, Khayn is the forename as well as the last name.