plaster of Paris

noun

Etymology: So named after a large gypsum deposit at Montmartre, Paris.

1. A hemihydrate of calcium sulfate, made by calcining gypsum, that hardens when moistened and allowed to dry; used to make casts, molds and sculpture.

   “So that in fact, the drinkers of green tea, as it comes to the Eng­lish market, indulge in a beverage of Chinese paint, and might imitate the paint by dissol­ving prussian blue and plaster of Paris in hot water.”

   “Treatment of an acute occult dislocation of the ankle consists of immobilization in a snugly fitting plaster-of-paris cast, with little padding.”