From The Food Encyclopedia by Jacques Rolland and Carol Sherman
An Italian sauce that gets its name from pestare, the technique of crushing or grinding its ingredients (basil leaves, garlic, olive oil and pine nuts) in a mortar (mortaio) and pestle (pestello). Historians believe pesto to be a descendent of the Roman garum sauce, part of a family of sauces mostly acidic and aromatic in character, very unlike our modern oil-based pesto and its many variations, which include combinations of mint, coriander, parsley, almond, pistachio and walnut.
