Cognomen Ачай (Achai 
, Ачай 
) , worldwide, is a rare family name. The cognomen Ачай is habitual in Malaysia, where it is a rare surname, Indonesia, where it is a very rare surname, and Israel. Measured by absolute frequency, it is commonest in Malaysia, Indonesia, and Nigeria. More prevalently, Ачай is the forename as well as the last name.