Cognomen Гаидар (Gaidar 
, Гаидар 
, Gaydar 
) , across the world, is a rare family name. The family name Гаидар is habitual in Estonia, where it is a rare surname, Georgia, and Russia, where it is a very rare surname. Not in comparison with a country's population, it is the most numerous in Russia, the United States, and India. Very seldom, Гаидар is the forename as well as the last name.