(in cooking) a receptacle containing hot or boiling water into which other containers are placed to warm or cook the food in them.
2.
British. a double boiler.
Origin: 1815–25; < F, MF, trans. of ML balneum Mariae lit., bath of Mary, reputed to be a Jewish alchemist who devised such a heating technique, and sometimes identified with Moses' sister Miriam
bain-ma·rie (bān'mə-rē') n.
pl.bains-ma·rie (bān'mə-rē') A large pan containing hot water in which smaller pans may be set to cook food slowly or to keep food warm.
[French, from Medieval Latin balneum Mariae, bath of Maria, probably after Maria, an early alchemist.]