The authors agree that this surname derives from a nickname linked to fennel, whether by the proximity of the dwelling to fields where this plant grew or by the trade of the one who cultivated or sold it. F. Miranda specifies the Latin origin: from the term fenucularium ("field of fennel"), and notes the dialectal forms finucchiara (the place) and u finucchiaru (the trade) as the base of the surname.

F. De Laurentiis adds that the names and nicknames Finocchio and Finocchiaro were already common from the 12th century, and that they could also have been generated from names of localities where fennel grew —mainly wild— or from figurative and allusive uses of the word.

As for the geographical distribution, Miranda indicates that the surname is spread through around 350 municipalities of almost all the regions of Italy. Its main nucleus is concentrated in eastern Sicily, especially in the Catania area, with ramifications towards the Messina, Syracuse, Palermo and Ragusa areas, as well as towards the area of Enna. Presence is also recorded in Lombardy, Lazio, Piedmont, Liguria and other regions.