Laser technology

The twenty-first entry is a largura de corte, and it is one of the few places on this page where English is the shorter language. The slot that a saw, a blade or a laser leaves behind has a noun of its own: « a kerf », the width of material a cut takes away and does not give back. It is an old word and a plain one. Old English had cyrf, a cutting, built on ceorfan, to carve, and the two have drifted apart ever since. « To carve » went to the table and to sculpture; « kerf » stayed in the workshop and never turned figurative at all, which is why it sounds technical to anyone who has never held a saw. Portuguese kept no such noun. It describes the thing instead, with two words and a preposition — a largura de corte, the width of the cut — and on a drawing that is exactly what has to be allowed for, since the part comes out smaller than the line by half a kerf on each side. English names the gap; Portuguese measures it.