Cognomen Sûn (Sûn 
, Сюн 
) , worldwide, is a very rare last name. The family name Sûn is habitual in Kyrgyzstan, where it is a very rare surname, Kazakhstan, and Ukraine. Not in comparison with a country's population, this name is the most popular in Russia, Ukraine, and Kyrgyzstan. Also, Sûn is the forename as well as the last name.