Cognomen ฤทธิดา (ฤทธิดา 
, Rittida , Ritdath ) , in the entire world, is an extremely rare last name. The family name ฤทธิดา is characteristic of South-eastern Asia, particularly Thailand, where it is an extremely rare surname. More prevalently, ฤทธิดา is the forename as well as the last name.