A double boiler is a kitchen tool that's typically used for melting chocolate, making desserts and sauces that require gentle heat. However, there are several different words that can be used as synonyms for double boilers. For example, there's bain-marie, which is a French term that refers to a similar tool that is used for the same purposes. Another synonym for double boilers includes water baths, which involve using pot or pan filled with water to gently heat food items in a separate container. You might also hear the term "pans in pans" being used to refer to the same tool, or even "stacked pans" which describes the usage of two pans of different sizes with a smaller one sitting inside the larger one.