According to E. Rossoni, the surname Vicari presents a main nucleus in Sicily, especially in the Palermo area, and another in the province of Rome. Its origin would be toponymic, derived from localities such as Vicari (Palermo) or Vicarello (Rome). On the other hand, the form Vicario —present in areas such as Varese, Udine, Rome, Caserta and Messina— would have a different origin, linked to the medieval term vicarius, which designated an official delegated by an authority to exercise a certain power in its name.

For his part, F. De Laurentiis agrees that Vicari may be a surname of toponymic origin, especially in Sicily, derived from Vìcari (PA). However, for forms such as Vicàri or Vicario, he also notes an origin based on a nickname or on a title of office, both in the civil and religious spheres. The term vicario was applied to one who exercised functions in representation of another authority —such as a parish, apostolic, imperial or judicial vicar—, which explains its use as a surname in different historical contexts.