Cognomen Khac (カク 
, Khac 
, Кхак 
) , around the globe, is quite a rare surname. The last name Khac is characteristic of Vietnam, where it is quite a rare surname, Japan, where it is a rare surname, and Lithuania. Measured by absolute frequency, it is commonest in Vietnam, Japan, and Malaysia. More frequently, Khac is the forename as well as the last name.