F. De Laurentiis and V. Blunda agree that the surname derives from a Germanic personal name, although they propose different interpretations.

De Laurentiis derives it from the personal name Rando, an aphaeretic hypocoristic of Brando or Prando.

Blunda, on the other hand, for the Sicilian variant derives it from the Germanic personal name Randu, linked to the root randu ("shield, reinforced edge of the defensive weapon") in its simple form, without a second compositional element.

Blunda specifies that the shield was a fundamental piece of the defensive armament of the free Germanic man, and that its ritual delivery marked the incorporation of the young warrior into the assembly of the adult free men, a legally binding event that sanctioned the passage to the full condition of member of the armed community. He notes that the variant Ranno presents the consonant assimilation with doubling of the nasal characteristic of medieval southern Italian.