E. Rossoni and P. Regati agree that the surname derives from a dialect form of the term riccio ("curly"), applied both as a nickname and as a name.

Rossoni notes that Risso is very diffused in the Milan and Pavia areas, throughout Piedmont and especially in Liguria. He adds that Rissolo is extremely rare and typical of the Turin area, and that it would be a diminutive form of the former; and that Rissone has a large area in Asti and its surroundings, and in Turin and its surroundings, with a small representation also in Genoa.

Regati defines it, from the Genoese risso ("of curly, densely wavy hair; curly"), as a typical Ligurian surname.

Other hypotheses link it to colour —from riso ("rust, reddish")— or to a descriptive nickname. It is also noted that it may derive from a minor place name or from a dialect form of riva ("coast"). It is identified as a typical Ligurian surname.