Cognomen Nihaj (Nihaj 
, Нихай 
) , worldwide, is a rare last name. The cognomen Nihaj is characteristic of Sri Lanka, where it is a rare surname, Greece, and Belarus, where it is a very rare surname. Not in comparison with a country's population, this name is the most popular in Sri Lanka, India, and Russia. Likewise, Nihaj is the forename as well as the last name.