Cognomen 西西 (西西 
, Seacy 
) , all around the world, is quite a rare last name. The last name 西西 is characteristic of Ireland, where it is a rare surname, China, and Australia, where it is a very rare surname. Not in comparison with a country's population, this name is the most popular in China, Ireland, and the United Kingdom. More frequently, 西西 is the forename as well as the last name.