The authors agree that the surname Negrelli derives from Negri, a form in turn related to the Latin Niger and its medieval derivatives Nigrus, Negro or Nigro. These surnames arose in many cases as nicknames linked to the colour of the hair or the skin, and in southern Italy they may also refer to descendants of Saracens.

E. Rossoni notes that the surnames of this lexical family show well-differentiated regional distributions: Negri is typical of northern Italy with a presence also in the Naples area; Negrini is very widespread throughout the north, especially in Lombardy and Emilia-Romagna; Negro has a core in the Salento area —that is, the southernmost zone of the region of Puglia— and is very widespread throughout Piedmont and Liguria; Negroni has an important core in the Bologna area with a presence in Lombardy.