The authors agree that this surname derives from a dialect nickname related to the Neapolitan verb scugnà (also scognà), which means "to thresh or clean cereals," combined with the term miglio ("millet"). It therefore refers to the activity of the cereal thresher.

E. De Felice notes that the surname is of southern formation and links it semantically with the Ligurian type Pittamiglio, suggesting that both share a similar metaphorical base linked to the processing of grain.

E. Rossoni specifies that the surname is typical of Campania, with a presence concentrated in the eastern zone of Naples and nearby municipalities such as Portici, San Giorgio a Cremano, Ercolano and Torre del Greco. Rossoni also mentions the variant Scognamillo, considerably rarer and of a more strictly Neapolitan character.