Family name Mordus (Mordus 
, Мордус 
) , all over the world, is a rare last name. The cognomen Mordus is habitual in Belarus, where it is a rare surname, Ukraine, where it is a very rare surname, and Kazakhstan. Measured by absolute frequency, it is the most numerous in Belarus, the United States, and Ukraine. Very seldom, Mordus is the forename as well as the last name.