Origins
Plastic existed as a word for nearly three hundred years before the material was invented. The adjective entered English in the 1630s from Latin plasticus, from Greek plastikós — 'fit for moulding' — from plássein, 'to mould, to shape'. The plastic arts were sculpture, ceramics, and metalwork: arts where the artist shapes raw material with their hands.
The Greek verb plássein traces to Proto-Indo-European *pleh₂- meaning 'to spread flat, to form'. From this root came plaster (a mouldable coating), plasma (the formless base of blood), protoplasm (the first-formed substance of a cell), and the medical suffix -plasty (rhinoplasty: nose-shaping).
The noun plastic appeared in 1905, when Leo Baekeland created Bakelite — the first fully synthetic polymer. The name was perfect: the material's defining property was that it could be moulded into any shape. What had been a quality of sculpture became the identity of a substance.
Later History
The negative connotations arrived later. By the 1960s, plastic meant cheap, fake, artificial. The 1967 film The Graduate famously used it as a symbol of hollow modernity. Environmental concerns in the 21st century added ecological damage to the word's baggage.
Yet the original Greek meaning endures in science and medicine. Neuroplasticity — the brain's ability to reshape itself — uses plastic in its purest sense: capable of being moulded.