In British (or British influenced) English the thing that Americans might call an undershirt/tank top/wifebeater is called a vest. What Americans call a vest is a waistcoat. Americans use pants and trousers interchangeably -- in UK British English pants (as clothing items) refers pretty exclusively to underwear and trousers are outerwear. These are only some of the examples where different versions of English use the same words to mean very different things.