Cognomen Siku (Siku 
, Siccus 
) , throughout the world, is quite a common surname. The surname Siku is habitual in Sub-Saharan Africa, particularly Botswana, where it is quite a rare surname, Namibia, and Angola. Measured by absolute frequency, this name is the most popular in India, Indonesia, and Kenya. Also, Siku is the forename as well as the last name.