According to E. Rossoni, these surnames come from a Provençal byname derived from the word fissa or fisse, which designates a type of schistose rock of black colour. It is possible that the first bearers received this denomination in allusion to a geological characteristic of their place of provenance.

• Fissi: It is a Tuscan surname, closely linked to the Florence area (including Scandicci and Sesto Fiorentino) and to Prato.

• Fissa and Fisso: They are recorded as unique local forms, probably lexical variants of the same root – although with different spelling, both preserve the original sense of "black schist".

• Fissore: Of Piedmontese origin, with quite a few bearers in the province of Cuneo and in the Turin area.