Distilling spirits in Italian

The twenty-fourth entry is il bicchiere da degustazione, and the small word in the middle carries a rule worth having whole. Italian marks purpose with da and content with di, and the two sit on the same noun without changing anything else in the phrase. Un bicchiere da vino is a wine glass, the shape kept in the cupboard for wine, empty at this moment and still called that. Un bicchiere di vino is a glass of wine, the thing somebody hands you. Swap the prepositions and the sentence stays perfectly grammatical while saying something else, which is why the mistake survives so long in a learner. The pattern runs far beyond the table: la sala da pranzo, le scarpe da ginnastica, il costume da bagno, gli occhiali da sole, la macchina da scrivere, il campo da tennis — in every one da names the job the thing is built for. English has no preposition here at all. It stacks the two nouns and lets order do the work, « a wine glass » against « a glass of wine », so a reader has to rebuild by position a distinction Italian writes out in a letter.