Waistcoat (although purists might claim that a waistcoat requires not only buttons, but a collar)
Pants (well, more commonly, underpants, but still.....)
Nappy ( my mother's group in Michigan thought this was hysterically funny - I still haven't worked out why, but it was an easy laugh anyway)
Bunny Rug (imagine a baby wrapped in this)
and best of all, confusing native English speakers from 2 continents
Tracky daks! (note, this is slang and my mother hates the term)
and here is one for the Australians from other states
I am fascinated by the range of English, such a flexible language.