A firm covering (often made of plaster of Paris) that immobilizes broken bones while they heal; SYN. plaster cast.

ETYM AS., a plaster, from Latin emplastrum, Greek, to daub on, stuff in; en in + plassein to mold: cf. Old Fren. plastre a plaster, French plâtre. Related to Plastic, Emplaster, Piaster.
A mixture of lime or gypsum with sand and water; hardens into a smooth solid; used to cover walls and ceilings.