Pesto (Italian pron. /'pesto/, genoese pron. /'pestu/, contracted past participle of pestâ: "to pound, to crush," in reference to the crushed herbs and garlic in it, from Latin root of pestle) is a sauce that originates in the city of Genoa in the Liguria region of northern Italy (pesto alla genovese).At least one other well-known variant exists, the pesto alla siciliana, a sauce from Sicily similar to the basic Genoese pesto recipe with the addition of tomato and much less basil.