Here are a few of the more common words which are different in American and British English.

the 1st.words in red are American English and the second words in blue are in British English.

apartment
flat

argument
row

baby carriage
pram

band-aid
plaster

can
tin

chopped beef
mince

cookie
biscuit

corn
maize

diaper
nappy

elevator
lift

eraser
rubber

flashlight
torch

fries
chips

gas
petrol

guy
bloke, chap

highway
motorway

hood (car)
bonnet

jello
jelly

jelly
jam

kerosene
paraffin

lawyer
solicitor

license plate
number plate

line
queue

mail
post

motor home
caravan

movie theater
cinema

muffler
silencer

napkin
serviette

nothing
nought

overpass
flyover

pacifier
dummy

pants
trousers

parking lot
car park

period
full stop

pharmacist
chemist

potato chips
crisps

rent
hire

sausage
banger

sidewalk
pavement

soccer
football

sweater
jumper

trash can
bin

truck
lorry

trunk (car)
boot

vacation
holiday

vest
waistcoat

closet
wardrope