The surname Passafiume is of occupational origin and derives from a dialectal expression alluding to the trade of “one who crosses the river,” that is, a ferryman or boatman. On this point E. De Felice, E. Rossoni and V. Blunda agree, noting that the surname arises from an occupational name tied to the transport of people and goods across watercourses.

E. De Felice interprets it as a compound of passa fiume, while V. Blunda specifies its dialectal form pàssa ciùmi, both with the same functional meaning. Along the same lines, E. Rossoni confirms its origin as an occupational nickname and documents its presence in Sicily since medieval times, which shows its consolidation as a hereditary surname from this activity.