E. Rossoni notes that this surname would derive from the medieval Germanic name Gerhald or from the Norman Geraldus or Giraldus, documented in the Chronicon Claraevallensi of 1192. Rossoni identifies specific zones of presence: the form Geraldi appears in the Crotone area, between Isola di Capo Rizzuto and Santa Severina, and also in the Agrigento area, in Sciacca. The variant Geraldini would seem to be typical of the Rome area, while Geraldino, Geraldo and Ieraldi are almost unique.

V. Blunda agrees on the Germanic root, but specifies that the surname is formed from the compound gaira-wald, where gaira means "spear" and wald, "power" or "command", with the general sense of "ruler of the spear" or "lord of the armament". Blunda highlights that the anthroponym Geraldo had a great diffusion in medieval Europe and gave rise to place names and derived forms in all the European languages. He also notes that the variants Gherardi and Ghirardi incorporate the spelling with an intercalated -h-, characteristic of northern Italy to indicate the guttural pronunciation of the consonant in intervocalic position.