The authors agree that this surname is of Sicilian origin and is widely diffused on the island. The etymological explanations divide into two broad lines, which are not necessarily mutually exclusive.

The first line points to a lexical root related to an agrarian measure. F. Miranda notes that the surname could derive from mondello, an adaptation of a southern word coming from the Arabic mudd, the name of a measure for cereals —in Latin moggio, in Greek μόδιος—, used in Palermo and in other Italian regions before the adoption of the metric decimal system. V. Blunda agrees with this line and specifies that the Sicilian dialect form is munnèddu, with the meaning "agrarian measure, unit of surface", and that as a surname it could have originated in a microtoponym applied to the holder of a plot identified by that measure.

The second line points back to personal names. E. Rossoni and Miranda agree that the surname could derive from diminutive or affectionate forms of names such as Edmondo or Raimondo. For their part, Rossoni and Miranda also mention the place name Mondello —a hamlet and tourist resort of Palermo— as a possible origin. Miranda, moreover, locates the surname at Catenanuova and Centuripe, in the province of Enna.