A sauce is a liquid or semi-liquid mixture used to enhance the flavor, texture, and appearance of food. Key features include flavor enhancement, moisture, versatility, and cultural significance. Common types include mother sauces (béchamel, velouté, espagnole, hollandaise, tomato) and international sauces like soy sauce, pesto, salsa, and barbecue sauce. Sauces can be used for cooking, marinating, dipping, or glazing.