Family name Dilaj (Dilaj 
, Дилай 
) , across the world, is a rare cognomen. The cognomen Dilaj is habitual in Azerbaijan, where it is quite a rare surname, Poland, where it is a very rare surname, and Morocco. Not in comparison with a country's population, it is commonest in Azerbaijan, Poland, and France. Also, Dilaj is the forename as well as the last name.