The Fonda, originally called Fundani/Fondani, derive from the Latin Gens Fundania of Rome, which means inhabitant of Fondi, a coastal city in Lazio between Terracina and Formia. They arrived in the medieval period first at Aquileia (where a distant ancestor —Lucius Fundanius Rufus— was a member of the Senate of Aquileia), after the destruction by Attila in 452, and later at Venice, following the barbarian incursions.

The Fonda branch reached Trieste in the 1700s, in particular at Servola, and then spread throughout the Karst of Trieste and Slovenia as far as Ljubljana, where they became Fundak.

In Trieste, they established themselves only after 1700. Fonda is a Triestine surname spread also in the Veneto and sporadically in the rest of Italy. It is a surname of Roman origin that arrived through Aquileia.