Laser technology

The thirtieth entry is l’indurimento superficiale, and the adjective inside it is the quietest trap on this page. Superficiale does two jobs in Italian with equal ease. It means belonging to the surface, flatly and technically: la tensione superficiale, uno strato superficiale, una bruciatura superficiale. And it means shallow, said of a reading, an argument or a person: un’analisi superficiale. English inherited both senses and then let the first one go nearly everywhere. « Superficial » is now heard as a verdict — a superficial remark, a superficial acquaintance — and it keeps the neutral reading only in a handful of fixed medical phrases, « a superficial burn », « the superficial veins ». Outside those, the engineer reaches instead for « surface » and uses it as a modifier: surface tension, a surface layer, surface hardening. So l’indurimento superficiale is « surface hardening », or « case hardening » in a workshop, and never « superficial hardening », which would report that the treatment had been done carelessly rather than that it stopped at the rim.