In all the world, Каю (Kayu 
, Каю 
) is quite a rare unisex given name. The first name Каю is habitual in Hong Kong, where it is quite a rare unisex name, Ethiopia, where it is a rare gender-neutral name, and Indonesia, where it is a rare dominantly masculine, but seldom feminine name. Measured by absolute frequency, it most frequently occurs in Indonesia, Hong Kong, and India. Much less frequently, Каю is the last name as well as the forename.