The authors agree that the surname was formed from a name or appellative of Lombard origin linked to the institution of the hariman ("free man in arms, belonging to the army").

E. De Felice specifies that it is the surname-formation of the names of Germanic origin Armanno or Ermanno, documented in Italy from the 10th century in the Latinised forms Hariman(n)us or Ariman(n)us, Arman(n)us, Herimannus and Hermannus.

De Felice notes that the Germanic personal name is of Lombard tradition —with later Frankish or German overlays for the forms in Arm- and Erm-—, and has as its base the noun hariman(n) ("arimanno"), that is "free man, belonging to the army, to whom the defence of strategic points and the ownership of inalienable rural estates is entrusted", formed from harja- ("army") and mann(o)- ("man").

De Felice adds that the surname is widespread mainly in northern Italy, and is rare in the centre and south.

It is considered, along a complementary line, to be a recurrent social nickname, derived from the Lombard hariman ("free man in arms").