The surname Aghilar is extremely rare and presents different interpretations depending on the author. On the one hand, E. Rossoni proposes a toponymic origin linked to Spain, noting that it would derive from Aguilar de la Frontera (Andalusia). In this sense, he also mentions the D'Aghilar as marquises of the Aragonese crown, cited by Guicciardini in his History of Italy in the second half of the 15th century, which suggests a possible noble connection and a diffusion linked to historical movements between Spain and Italy.

On the other hand, F. De Laurentiis puts forward a different interpretation, relating the surname to personal names of Germanic origin such as Aghinolfo or Aiolfo, frequent in the Middle Ages. These names are documented from the 11th century in regions such as Piedmont and Tuscany in Latinised forms such as Aghinolfus, Aginulfus, Aiolfus and Aiulfus, which opens the possibility of an anthroponymic origin independent of the Hispanic sphere.