water bath means: This cooking method is called “bain marie” by the French. This involves placing food into a shallow, large pan filled with warm water. The food is then heated gently. This can be done in an oven, or over a grill. It is used to prepare delicate foods such as sauces, custards, and savory mousses. You can use it to heat foods. (in Cooking Dictionary)

What else does water bath mean?

Place a container with food into a pan filled with warm water. The heat surrounds the food. Water baths are used for cooking custards and sauces and to preserve food heat. (in Cooking Dictionary)