plaster: [OE] Like plastic, plaster comes ultimately from the Greek verb plássein ‘mould’. Combination with the prefix en- ‘in’ produced emplássein ‘daub on, plaster’. From its past participle emplastós was derived émplastron ‘medicinal application to the skin’, which reached Latin as emplastrum. Medieval Latin shortened it to plastrum, which Old English adopted as plaster. Its use for a ‘soft substance spread on walls, etc’ was introduced via Old French plastre in the 14th century. => plastic[plaster etymology, plaster origin, 英语词源]