plastic (n.)
1905, "solid substance that can be molded," originally of dental molds, from plastic (adj.). Main current meaning, "synthetic product made from oil derivatives," first recorded 1909, coined by Leo Baekeland (see bakelite).
plastic (adj.)
1630s, "capable of shaping or molding," from Latin plasticus, from Greek plastikos "able to be molded, pertaining to molding, fit for molding," also in reference to the arts, from plastos "molded, formed," verbal adjective from plassein "to mold" (see plasma). Surgical sense of "remedying a deficiency of structure" is first recorded 1839 (in plastic surgery). Meaning "made of plastic" is from 1909. Picked up in counterculture slang with meaning "false, superficial" (1963). Plastic explosive (n.) attested from 1894.