E. Rossoni notes that the surname Fior, together with variants such as Fiore, Fiori, Fioretti, Fiorio and Fioroni, would derive from the Latin cognomen Florens, from the nomen Florius, from the medieval name Fiore, or from place names with the root fiore, such as San Giovanni in Fiore or Santa Maria del Fiore. Rossoni documents the use of this name in Cividale in the year 1409, and places Fior as typical of the Venetan-Friulian area, with presence mainly in the Padua, Treviso, Pordenone and Udine areas.

E. De Stefani provides a more localised perspective and specifies the etymology: the base name, Flôr, goes back ultimately to the Latin flos, "flower", which was used with an augural function —it was wished that the bearer be pure and beautiful like a flower— and could be assigned both to women and to men. De Stefani also links the popularity of the name to the literary figure of Blancheflor in the late medieval romances. Over time, Flôr became a surname.

De Stefani documents the surname in the Carnia —a mountainous zone of the north of Friuli, in the province of Udine—.