In all the world, Isay (Исай 
, Isay 
, 伊赛 
) is quite a rare principally masculine, but very infrequently feminine first name. The forename Isay is habitual in Bulgaria, where it is quite a common boy's name, Israel, where it is quite a rare boy's name, and Russia, where it is a rare masculine name. Not in comparison with a country's population, it is the most numerous in Russia, Bulgaria, and Mexico. Likewise, Isay is the last name as well as the forename.