The authors agree that this surname derives from the medieval appellative signore, in turn coming from the oblique case of the Latin senior, senioris, with the meaning of "old man" and, by extension, "lord, prince, head of a state or of a fief, high magistrate." The term functioned first as a title of consideration, then as a nickname and finally as a proper name before transforming into a surname.

E. De Felice notes that the forms Signori (in the dative), Signorellus and Signorettus are documented as early as the 11th and 12th centuries. He adds that the variants of the surname present differentiated regional distributions: Signore is proper to the south of Italy, together with Signorile —very frequent in Apulia— and Signorino; Signoriello predominates in the Naples area, while Signorini has a greater presence in Tuscany.

F. De Laurentiis highlights that the surname is diffused throughout Italy with variable distribution and frequency, and incorporates among the meanings of the base term that of "landowner."