Cognomen Горностаи (Gornostay 
, Горностаи , Gornostai ) , throughout the world, is a very rare surname. The cognomen Горностаи is habitual in Belarus, where it is a rare surname, Israel, where it is a very rare surname, and Russia. Measured by absolute frequency, the name is most common in Russia, Belarus, and the United States. Very seldom, Горностаи is the forename as well as the last name.