​PLASTER, a mixture of lime, hair and sand, used to cover rough walling of lathwork between timbers (see Plaster-work), also a line white plaster of gypsum, generally known as “plaster of Paris” The word (also as “plaister”) is used in medicine of adhesive mixtures employed externally for the protection of injured surfaces, for support of weak muscular or other structures, or as counter-irritants, soothing applications &c. The ultimate derivation of the word is the Gr. έμπλαοτρον or έμλαστον in the medical sense, from έν, on, and πλάσσειν to daub or smear.