Mayonnaise, colloquially referred to as "mayo", is a thick, cold, and creamy sauce or dressing commonly used on sandwiches, hamburgers, composed salads, and French fries. It also forms the base for various other sauces, such as tartar sauce, fry sauce, remoulade, salsa golf, and rouille.
Mayonnaise is an emulsion of oil, egg yolk, and an acid, either vinegar or lemon juice; there are many variants using additional flavorings. The color varies from near-white to pale yellow, and its texture from a light cream to a thick gel.
Commercial eggless imitations are made for those who avoid chicken eggs because of egg allergies, to limit dietary cholesterol, or because they are vegans.