This topic was suggested by a friend as there are some significant differences between ‘American English’ and ‘English English’:
In America, a women’s fanny is her backside. In Britain it’s (ahem) a more intimate part of the female body. I recall that I once performed in an amateur production of ‘Arsenic and Old Lace’ which featured the instruction “Mortimer pats Elaine on the fanny.” – you can see the potential confusion.
Fanny is also military slang for a mess tin, after the tragic story of Fanny Adams who was brutally murdered and butchered in the village of Alton in Hampshire in 1867. Her body was so badly butchered that the term ‘sweet Fanny Adams’ or ‘sweet FA’ became synonymous with poor quality canned meat and later with something of negligible worth.
To Brits ‘bum’ refers to what Americans would call a ‘fanny’. The polite casual term is ‘bottom’ and a less polite version is ‘arse’ – note the difference in spelling.
What Americans call ‘fanny packs’ we Brits call ‘bum bags’.
We Brits don’t use the term ‘bum’ (or hobo) to refer to vagrants, we normally call them ‘tramps’ – and that’s all we tend to call tramps.