Cognomen ซิ่ว (Sio 
, Siou 
, Siuw ) , throughout the world, is a common surname. The cognomen ซิ่ว is habitual in Macao, where it is a common surname, Mozambique, where it is quite a rare surname, and Papua New Guinea. Not in comparison with a country's population, it is the most numerous in Macao, Mozambique, and Philippines. Likewise, ซิ่ว is the forename as well as the last name.