The authors agree that this surname derives from the medieval Germanic name Sighinolfo, composed of sigu ("victory") and wulfa ("wolf"). Both also agree that this name is documented in northern Italy from the 9th century.

E. De Felice records the Latinized forms Sigenulfus and Sigulfus, attested from the year 880, and interprets the original meaning as "wolf, valiant fighter for victory," considering that the wolf was a sacred animal symbol of strength and daring. He further notes regional variants: Sghinolfi in Emilia and Sichinolfi or Siconolfi in southern Italy, especially in the region of Campania.

E. Rossoni specifies that the surname is typical of the Modena area, with a notable presence in Nonantola. He contributes that among the historical bearers of the base name figures a Lombard duke of Benevento documented in the year 848, and notes that the name also appears in the Decameron of Boccaccio.