Cognomen Zykus (Zykus 
) , all over the world, is a rare surname. The last name Zykus is characteristic of Lithuania, where it is quite a rare surname, Australia, where it is a very rare surname, and Canada, where it is an extremely rare surname. Not in comparison with a country's population, it is the most numerous in Lithuania, Australia, and Russia. Very seldom, Zykus is the forename as well as the last name.