Chemistry and materials

The twelfth entry is l’acido, and it is worth stopping there, because the word began by naming a taste rather than a chemical property. Latin acidus meant sharp on the tongue, sour, the quality of vinegar, and it was built on a root that runs through the whole Latin vocabulary of edges and points: acies, the cutting edge of a blade, acer, keen, acus, a needle. That root is why l’acido has a relative seven entries further down this same page. Late Latin called hardened iron ferrum aciarium, the metal made for an edge; aciarium went on alone and became l’acciaio, the steel of l’acciaio inossidabile. English holds nearly the whole family as loans — « acid », « acute », « acrid », « acerbic », and, by way of the French aigre, both « eager » and the sour wine inside « vinegar ». The one member it did not borrow is the metal. For that it kept a Germanic word, « steel », so the place where the family is plainest in Italian is exactly the place English hides it.