Family name Sung-Yoon (성윤 
, Sung-Yoon 
) , around the globe, is an extremely rare cognomen. The surname Sung-Yoon is habitual in Northern America, particularly the United States, where it is an extremely rare surname. Much more frequently, Sung-Yoon is the forename as well as the last name. Parts of the name also exists independently as a last name Sung, and a first name Yoon.