Source : Webster's Revised Unabridged Dictionary (1913)

Plaster \Plas"ter\, n. [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. pl[^a]tre.
   Cf. {Plastic}, {Emplaster}, {Piaster}.] [Formerly written
   also {plaister}.]
   1. (Med.) 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 fertilizer.

   {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.] (Chem.) Anhydrous calcium
      sulphate, or calcined gypsum, which forms with water a
      paste which soon sets or hardens, and is used for casts,
      moldings, etc. The term is loosely applied to any plaster
      stone or species of gypsum.

   {Plaster of Paris bandage} (Surg.), a bandage saturated with
      a paste of plaster of Paris, which on drying forms a
      perfectly fitting splint.

Plaster \Plas"ter\, v. t. [imp. & p. p. {Plastered}; p. pr. &
   vb. n. {Plastering}.] [Cf. OF. plastrer to plaster (in sense
   2), F. pl[^a]trer.]
   1. To cover with a plaster, as a wound or sore.

   2. To overlay or cover with plaster, as the ceilings and
      walls of a house.

   3. Fig.: To smooth over; to cover or conceal the defects of;
      to hide, as with a covering of plaster. --Bale.

Source : WordNet®

plaster
     v 1: cover conspicuously, as by pasting something on; "The
          demonstrators plastered the hallways with posters"
     2: affix conspicuously; "She plastered warnings all over the
        wall"
     3: apply a plaster cast to; "plaster the broken arm"
     4: apply a heavy coat to [syn: {plaster over}, {stick on}]
     5: coat with plaster; "daub the wall" [syn: {daub}]
     6: dress by covering with a therapeutic substance [syn: {poultice}]

plaster
     n 1: a mixture of lime or gypsum with sand and water; hardens
          into a smooth solid; used to cover walls and ceilings
     2: 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 limbs [syn: {plaster of
        Paris}]
     3: 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. [syn:
        {poultice}, {cataplasm}]
     4: a hardened surface of plaster (as on a wall or ceiling);
        "there were cracks in the plaster" [syn: {plasterwork}]
     5: adhesive tape used in dressing wounds [syn: {adhesive
        plaster}, {sticking plaster}]