The fashion industry in Italian

The eleventh entry is la solidità del colore, and the English name for it hides a word every reader thinks they already know. The laboratory tests it by rubbing and by washing and calls the result « colour fastness »: a dye is « fast to washing », « fast to light », « fast to rubbing ». Nothing in any of that is quick. This « fast » is the older of the two, from Old English fæst, firm and fixed, and it is still alive in « hold fast », « stuck fast » and in the verb « to fasten ». The sense of speed grew out of the adverb, where running « fast » was first running firmly and vigorously and only afterwards running quickly. A fast colour, then, is a colour that will not let go. Italian never made that journey and names the same property from the other side, by what the dye is rather than by what it withstands: solido gives la solidità. A reader who takes « colour fastness » for a measure of speed has translated a word that had stopped meaning speed long before there was a dye industry.