In the 14th century in Montieri (GR) there was a bishop named Ser Tuccio, and in Florence one Giovanni di Tuccio degl'Infangati. Since at the time no surnames as such were in use, this Tuccio was probably a diminutive form of names anding in "-to" as Alberto, Roberto, Santo, Vito and others.
Reference:
"domina Lecta, uxor olim Tucci de Infangatis, populi Sancte Cecilie, cum consensu" a lady giving receipt for a rental. The Infangati family was recorded among the noble families in Florence in the years 1293-95 in: G. Salvemini, Magnati e popolani in Firenze dal 1280 al 1295, Firenze 1899, 376a. Necr. I, 68, 393-402; II, 642b. SOPMÆ IV, 172-73.
The listings below are based on research in the white pages, last updated Jan 2009.
Tucci:
The surname is relatively common with about 3000 listings in the Italian white pages and is widespread in Italy, appearing in over 700 different comuni.
Ellis Island: over 1200 arrivals for Tucci immigrants are recorded.
White Pages: Tucci also appears in the United States with over 300 listings, in Canada with 347 listings, in Argentina with 587.
Tuccio:
The surname Tuccio appears in Italy with over 540 listings, appearing in over 159 different comuni, mostly concentrated in Sicily and Lombardy.
White Pages: Tuccio appears in the United States with over 300 listings, in Canada with only some listings, in Argentina with 39 listings.
Ellis Island: 158 arrivals for immigrants are recorded, coming mostly from Sicily.