Cognomen ארנולדי (Arnoldi 
, ארנולדי 
) , worldwide, is quite a common family name. The cognomen ארנולדי is characteristic of Italy, where it is quite a rare surname, Denmark, and Switzerland. Measured by absolute frequency, this name is the most popular in Italy, Indonesia, and Germany. Much less frequently, ארנולדי is the forename as well as the last name.