A Sauce, a french wordis a liquid cream, or semi-solidfood served on or used in preparing other foods.The oldest recorded European sauce is garum, used by the Ancient greeks; while dounbanjiang was used the Chinese in the 3rd century BC. 

Dips are used to add flavor or texture to a food

Spreads are added to food to enhance the flavor or texture of the food, which may be considered bland without it.