Meaning

noun a mixture of lime or gypsum with sand and water; hardens into a smooth solid; used to cover walls and ceilings

noun any of several gypsum cements; a white powder (a form of calcium sulphate) that forms a paste when mixed with water and hardens into a solid; used in making molds and sculptures and casts for broken l

noun a medical dressing consisting of a soft heated mass of meal or clay that is spread on a cloth and applied to the skin to treat inflamed areas or improve circulation etc.

originFrom Middle English plaster, plastre, from Old English plaster, from late Latin plastrum, shortened from Classical Latin emplastrum (“a plaster, bandage”); later reinforced by Anglo-Norman plastre. Displaced native Old English clīþa. The verb is from Middle English plastren, from the noun.

Etymology from Wiktionary, CC BY-SA 3.0