Here are some examples that you shared with us:
Pants: NA = trousers; UK = underwear
Rubber: UK = eraser!
Fit: UK = slang for sexy or attractive; NA = in good physical condition
Specialty (NA) vs Speciality (UK)
Artefact (UK) vs Artifact (NA)
A fanny in American means your bottom but in England that means a lady's private parts.
"Color" and "colour"
When I first moved to the US, I got a strange look from a builder when I told him his partner had popped out for a fag.
In England that means you've stepped outside for a cigarette. Apparently it means something quite different over here :)
got - NA's say gotten
F. M. Meredith
Knocked up: Meaning pregnant in NA--and I think going to someone's house and knocking on their door or visiting in the UK.
JD (The Engine Room)
Americans don't tend to use 'gone missing' to mean 'disappeared', and that they also don't use the verb 'to busk' (perform in the street for money).
I always assumed that the American English 'I could care less' was an elision of 'As if I could care less', which would be acceptable in British English too.
And here are some more of my favourites:
Puttering around (NA)Funnily enough, if you told an Australian you were "puttering" they might think you were in a tinny (a small motor boat). More Aussie vernacular coming up in this series.
Pottering around (UK)
Shopping cart (NA)(also known as a "trundler" in New Zealand and a "buggy" in some US states)
Shopping trolley (UK)
Program (NA/UK)In UK terminology "program" refers to computer programs, whereas "programme" is anything non-computer related such as a programme for a play, a TV show, etc.
Snicker (NA)(Although I can understand why this has been changed in the US.)
Trash can (NA)
Rubbish bin (UK)
Love on / hate on / beat up on someone (NA)
Love / hate / beat someone up (UK)
Full stop (UK)
Exclamation point (NA)
Exclamation mark (UK)
Elsa Neal is a writer based in Melbourne, Australia. Visit her website to download her free mini report on the Ten Most Frustrating Grammar Rules and How to Remember Them. Stay and browse through her resources for writers or follow her writing insights at her Fictional Life Blog.