The Collaborative International Dictionary of English v.0.48:

Plasterwork \Plas"ter*work`\, n.
   Plastering used to finish architectural constructions,
   exterior or interior, especially that used for the lining of
   rooms. Ordinarly, mortar is used for the greater part of the
   work, and pure plaster of Paris for the moldings and
   ornaments.
   [1913 Webster]

WordNet (r) 3.0 (2006):

plasterwork
    n 1: a surface of hardened plaster (as on a wall or ceiling);
         "there were cracks in the plaster" [syn: plaster,
         plasterwork]