seasoned pureed condiment widely used in the United States and Great Britain. American ketchup is a sweet puree of tomatoes, onions, and green peppers flavoured with vinegar and pickling spice that is eaten with meats, especially beef, and frequently with french fried potatoes (British chips); it is the universal condiment of certain fast-food sandwiches. In Britain, as formerly in the United States, ketchup is a puree based on mushrooms, unripe walnuts, or oysters; this ketchup functions primarily as a seasoning for cooking. The word derives from the Chinese ke-tsiap, a fish brine, probably by way of the Malaysian ketjap.