The authors agree in noting the Greek origin of the surname, linked to the term παιδάκι (paidaki), with the meaning of "child" or "boy." G. Rohlfs specifies that in Greece it survives as a surname under the form Pedakis, and considers Pedaci a sister form of Pedace.

E. Rossoni puts forward two hypotheses to explain the origin of the surname. The first links it to the Cosenza place name Pedace, though he notes that this place name in turn derives from a surname. The second hypothesis, which Rossoni extends to the whole set of Calabrian surnames of this family, relates it to the medieval nickname or name Pedace, an adaptation of the Greek paidakis, in correspondence with Italian surnames of equivalent meaning such as Fante, Infante or Fanciullo.

As to geographic distribution, Rohlfs places the surname in Calabria, with a presence in Cosenza, Reggio Calabria and localities of the province of Cosenza such as Corigliano and Crosìa. Rossoni describes it as typically Calabrian, with clusters in the Crotone area and in the Cosenza area —including Rossano, Corigliano Calabro, Crosia, Spezzano della Sila and Longobucco. The variant Pedaci, on the other hand, is characterised by Rossoni as proper to the Salento area —that is, the southernmost zone of the region of Apulia, in southern Italy—, with a presence in Gallipoli and in the Lecce area.