The authors agree that this surname derives from the word còcco, although they differ as to its underlying etymology. E. De Felice notes that it is the transformation into a surname of names and nicknames already documented from the 11th century (forms such as Coccus, Cocculus), and that the etymological bases are multiple and often not distinguishable from each other. The main word is còcco —with regional variants such as the Sardinian kókku—, a familiar term of onomatopoeic origin that, besides meaning "egg", functioned as an affectionate appellative for children and loved ones. De Felice also mentions regional or altered forms of cucco, with the sense of "cuckoo" or "very old, doting man", and refers to the word cuòco as another possible base.

V. Blunda, on the other hand, proposes a Greek etymology: the surname would come from còccos, meaning "grain, seed". According to this author, the word would have motivated the nickname by the short stature of the ancestor or by some trait associated with the object, and he notes its parallelism with the surname Coccia.

As for the geographical distribution, De Felice indicates that the form Cocco predominates in southern Sardinia, and that Cocchi occurs in Tuscany, Emilia and Lombardy. The forms Coccón and Coccato are peculiar to the northeast of Italy, in the regions of Veneto, Friuli-Venezia Giulia and Trentino-Alto Adige, while Coccaro and its derivatives correspond to southern Italy. Blunda, for his part, circumscribes his observation to Sicily.