E. Costantini proposes that the surname is probably an aphaeretic form —that is, with loss of the initial syllable— of Jocopetti, derived in turn from Jacopo, a variant of Giacomo. He documents it in Gemona at least from 1575, noting that it is typical of that locality of Friuli.

E. De Stefani offers a more detailed analysis and agrees on the starting point: the surname continues the Latin name Jacobus, of Hebrew origin, through the old Friulian variant Jacop. With the suffix -èt and the loss of the initial syllable, the given name Copèt was formed, which over time became the Italianized surname Copetti. De Stefani documents it in Tolmezzo, in the Carnia —a mountainous zone of the north of Friuli, in the province of Udine—, from the beginning of the 17th century, with presence also in other Friulian communities.

Both authors agree, then, that the surname derives from the name Jacopo or Jacobus through aphaeresis and suffixation, and that its area of origin is found in Friuli.