Ketchup or catsup is a table condiment with a sweet and sour flavor. The unmodified term ("ketchup") now typically refers to tomato ketchup, although early recipes for various different varieties of ketchup contained mushrooms, oysters, mussels, egg whites, grapes or walnuts, among other ingredients.

A condiment is a preparation that is added to food, typically after cooking, to impart a specific flavor, to enhance the flavour, or to complement the dish. A table condiment or table sauce is more specifically a condiment that is served separately from the food and is added to taste by the diner.