E. De Felice notes that this surname derives from the medieval title siniscalco ("seneschal"), a term coming from the Frankish siniskalk, composed of seno- ("old") and skalka- ("servant"). In the Germanic world it designated the steward of the royal and feudal houses, and later a high official of the imperial courts. In southern Italy, during the Norman, Swabian, Angevin and Aragonese dominations, the "Grand Seneschal of the Kingdom" was one of the seven great officers, superintendent of the royal house and member of the council of the crown.

E. Rossoni agrees on the origin of the office, although he specifies the etymology as derived from the late Latin siniscalcus ("older servant"). According to Rossoni, the variant Siniscalchi is very diffused in Campania, with a presence in Salerno, Naples and in the Avellino area —particularly in Quindici and Lauro—, besides zones in Crotone, Palermo and Syracuse. The variant Siniscalco, on the other hand, presents more limited nuclei in Baronissi, in the Salerno area, and in Naples.