1. (Science: medicine) An external application of a consistency harder than ointment, prepared for use by spreading it on linen, leather, silk, or other material. It is adhesive at the ordinary temperature of the body, and is used, according to its composition, to produce a medicinal effect, to bind parts together, etc.; as, a porous plaster; sticking plaster.
2. A composition of lime, water, and sand, with or without hair as a bond, for coating walls, ceilings, and partitions of houses. See mortar.
3. Calcined gypsum, or plaster of paris, especially when ground, as used for making ornaments, figures, moldings, etc.; or calcined gypsum used as a fertiliser. Plaster cast, a copy of an object obtained by pouring plaster of Paris mixed with water into a mold. Plaster of Paris. So called because originally brought from a suburb of Paris.
(Science: mathematics) A bandage saturated with a paste of plaster of paris, which on drying forms a perfectly fitting splint. Plaster stone, any species of gypsum. See Gypsum.
Origin: AS, a plaster (in sense 1), fr. L. Emplastrum, Gr, fr. To daub on, stuff in; in – to mold: cf. OF. Plastre a plaster (in sense 2), F. Platre. Cf. Plastic, Emplaster, Piaster Formerly written also plaister.