The following is a list of common British words that are not common in the U.S., including words that have different meanings in Great Britain and the U.S.:
advert: advertisement
Alsatian: German shepherd
Aunt Sally: easy target
banger: sausage
barrow: push-cart
bespoke: custom-tailored
billion: 1,000,000,000,000 (U.S. trillion)
bomb: great success (opposite of the U.S. meaning)
bonnet: car hood
boot: car tunk
braces: suspenders
brolly: umbrella
building society: savings and loan association
caravan: trailer
car park: parking lot
carriage: railroad passenger car
catapult: slingshot
chemist: pharmacist
chips: French-fried potatoes
clanger: blunder
conk: nose
cornet: ice-cream cone
costermonger: pushcart peddler
cotton wool: absorbant cotton
crisps: potato chips
draughts: checkers (the board game)
drawing pin: thumbtack
dual carriageway: divided highway
dummy: baby's pacifier
dustman: garbage collector
estate car: station wagon
Father Christmas: Santa Claus
first floor: second floor (the British begin counting above the ground floor)
flannel: washcloth
flat: apartment
flex: electric cord
flutter: small bet
football: soccer
Girl Guide: Girl Scout
glasshouse: greenhouse, military prison
hire-purchase: installment plan
hoarding: billboard
ironmongery: hardware store
jelly: gelatin dessert
jumble sale: rummage sale
ladder: run in a stocking
lashings: large servings of food or drink
lido: beach resort
lift: elevator
lorry: truck
milk float: dairy home-delivery truck
moggy: pet cat
nappy: diaper
nark: police informer
noughts-and-crosses: tic-tac-toe
nursing home: small private hospital
panda car: police patrol car
pants: underpants
patience: solitaire (card game)
petrol: gasoline
pissed: drunk
plimsolls: sneakers
point: electrical outlet
pontoon: twenty-one (card game)
pram: baby carriage
redcap: military police officer
return ticket: round-trip ticket
roundabout: traffic circle, merry-go-round
rubber: eraser
runner beans: string beans
serviette: napkin
silencer: car muffler
singlet: undershirt
steps: stepladder
subway: underpass
torch: flashlight
tram: streetcar
trolley: cart
trousers: pants
trunk call: long-distance call
tube: subway
tunk: trunk
turnup: trouser cuff
vest: undershirt
waistcoat: vest
warder: prison guard
wellies: rubber boots
wholemeal: whole-wheat
windcheater: windbreaker
windscreen: windshield
wing: fender
Please add more terms to this node if you know any that I failed to include.