Surname Ivaš (Иваш 
, Ivaš 
) , in the world, is a very rare last name. The family name Ivaš is characteristic of Belarus, where it is a rare surname, Kyrgyzstan, where it is a very rare surname, and Kazakhstan. Measured by absolute frequency, this name is the most popular in Belarus, Russia, and Kazakhstan. Also, Ivaš is the forename as well as the last name.