Plastics engineering

The sixteenth entry is il plastificante, and the word inside it is far older than the industry that uses it. Greek had plastikos, built on plassein, to shape or to mould. It named no substance at all: it named a property, the quality of taking a form and holding it. English received it as an adjective and used it that way for centuries, and that adjective is still at work in three familiar places. « The plastic arts » are the ones that shape matter. « Plasticity » is what a physicist says of a metal that deforms and does not spring back. And « plastic surgery » contains no plastic of any kind: the surgeon reshapes tissue, and the name says only that. Not until the twentieth century did the adjective harden into a noun for a class of materials, and that noun is now so loud that the older sense sounds like a joke. Il plastificante belongs to the adjective rather than to the noun. It is the additive that lets a stiff polymer take a shape, which is exactly what plastikos meant before anybody had made one.