1. strangely, it is a lenght measure

If you ask simply 'a coffee', in Italy, the barman will serve you an 'espresso': very 'tight' and concentrated. If you want what is also called (here in Italy) an 'American cofee', you should ask a 'caffè lungo', word by word, 'a long coffee'. In Italian we say 'lungo' or 'allungato' for drinks and liquid food when they are not concentrated, and probably less tasteful. It can be a soup, red wine, orange juice etc.