The acronym "Ruisseau du Sot" later becomes usage to designate this watercourse; this variant reflects the spelling used in Bouchette's time. It refers to a sault which is defined as a more or less significant slope break or a fall. The toponym "Petite rivière Saint-François" was formalized on August 17, 1978 at the Place Names Bank of the Commission de toponymie du Québec.