pesto UK /ˈpɛstəʊ/US /ˈpɛstoʊ/ noun1 •A sauce, especially for pasta, originating from the Genoa region in Italy, made from basil, garlic, pine nuts, olive oil and cheese (usually pecorino).For variation, easy cooking and good eating, slather some pesto on the fish of your choice and bake. — 1988 formspestos