A. Bongioanni notes that Teresa derives from the Greek feminine given name therasia, meaning "huntress", and that its name day is celebrated on 15 October. He indicates that in Piedmont the affectionate terms Gin and Ginota are associated exclusively with Teresa, which would explain the origin of the Monferrato surnames Ginacca and Ginatta. From the masculine form Teresio, he also proposes the derivatives Resio, Resi, Resinelli and Rasini.

E. Rossoni offers a different perspective for the variants Teresa and Teresi. He considers that they could derive from ethnic forms linked to the village of Terrasini, in the Palermo area, or in some cases from the Latin name Teresius. The variant Teresa would seem to be typical of Sicily, with a presence in Lampedusa, Linosa and the Trapani area. Teresi, more widespread, has a main stem in Palermo and a notable presence in Trabia, Termini Imerese and Marsala.