The authors agree that the surname has Germanic roots: E. Rossoni notes that it shares its root with the Lombard name Wildo or Wido and with the Germanic name Guildo. F. Miranda, by contrast, proposes a different etymology: the surname, far from being simply the feminine of Guido, would derive from the Italian verb guidare ("to lead"), as a nickname given to someone known for his ability to guide his family or community, following V. Di Criscito.

Rossoni documents its geographical distribution in detail: the surname is found throughout Italy, with a low concentration in the centre. He further notes that the related surnames Guido and Guidone show cores in Liguria, Naples, Apulia —especially in the Salento area, that is, the southernmost zone of the region of Puglia, in southern Italy—, Calabria in the Cosenza area, and in the Foggia and Messina areas.

Miranda broadens the distribution with regional data: the surname appears mainly in Campania, Apulia, Sicily, Lombardy, Lazio, Piedmont, Basilicata, Emilia-Romagna, Tuscany and Calabria. In Sicily it is present in several provinces, including Palermo, Trapani, Agrigento, Caltanissetta and Messina, with a documented presence in the Enna area.