bain-marie n 1: a large pan that is filled with hot water; smaller pans containing food can be set in the larger pan to keep food warm or to cook food slowly
Bain-marie \Bain`-ma`rie"\, n. [F.] A vessel for holding hot water in which another vessel may be heated without scorching its contents; -- used for warming or preparing food or pharmaceutical preparations. [1913 Webster]