Here, just for fun, is my definitive guide to Aussie/American translations. Some are obvious and well known from years of exposure to American TV and films; some are minor... and some can just be downright awkward.
I wasn't sure how to classify it on my list, but let's just say that while fanny can be innocent enough amongst Americans, in Australia, we'll think you're referring to your vagina. True. The word fanny pack will still make us double over in laughter.
I had to learn some of these the hard way - cornflour in the US (strictly for baking use) is entirely different to cornflour in Australia. I had a few failed stove-top sauces and soups before I worked that out. I mean, it looked different in the packet (I should have realised then) but so do a lot of things here. Turned out cornstarch is what I needed to thicken things. Thank you, Google and Chowhound.
Then there was the time I spoke to the staff at the leasing office of our apartment complex. We'd been having issues with the kitchen tap, and you should have seen the blank looks I received when I asked for the tap to be fixed. Yes, I knew the word faucet, but I'd completely forgotten about it - this was in the first few weeks here, when I was still getting by on the broken sleep of a newborn.
More recently, every time the Faery's teacher talks about trimesters, I keep glancing at her belly. It's a word I've only ever associated with pregnancy.
Anyhow, the language teacher in me felt the need to compile a list. It's by no means complete - feel free to suggest words that I can add - and I'm not even touching phrases, spelling or pronunciation. Not yet.
(My Australian vocabulary may be Sydney-centric in some examples, as things can vary from state to state - likewise, some of my American examples may be more Californian-speak than general)
I am such a language nerd at times.
A-K
arse - ass
autumn - fall
bill (restaurant) - check
bin - trash
biscuit - cookie
breastfeeding - nursing
bonnet (of car) - hood
boot (of car) - trunk
bubbler - drinking fountain
bum - butt
bum bag - fanny pack
CBD (central business district) - downtown
capsicum - bell pepper
caster sugar - baker's sugar
car park - parking lot
chickpeas - garbanzo beans
cinema - (movie) theater
cornflour - cornstarch
cot - crib
cutlery - flatware
doona (quilt) - comforter
dummy - pacifier
fairy floss - cotton candy
flat/unit - apartment
fringe (hair) - bangs
footpath - sidewalk
g-string - thong
give way (driving) - yield
grill (cooking) - broil
holiday - vacation
hoodie - sweatshirt
ice block - popsicle, ice pop
icing sugar - confectioner's sugar
indicator (car) - signal
jam - jelly
jumper - sweater
kebab (skewer) - kabob
L-Z
lemonade (such as Sprite) - lemon-lime soda
letter box - mail box
lift - elevator
lolly - candy
lollypop person - crossing guard
minced meat - ground meat
mobile (phone) - cell phone
nappy - diaper
notes (dollars) - bills
old-fashioned lemonade - lemonade
overtake (driving) - pass
pedestrian crossing - cross walk
petrol - gas
plain flour - all purpose flour
poo - poop
porridge - oatmeal
postcode - zipcode
pram - stroller
queue - line
rocket (lettuce) - arugula
rockmelon - cantaloupe
rubbish - garbage
sultana - raisin
scone - biscuit
soft drink - soda drink
tap - faucet
teat (on baby bottles) - nipple
term (school) - trimester
thongs - flip-flops
thrush - yeast infection
timber - lumber
tinned (food) - canned
toilet (public) - restroom
toilet training - potty training
tomato sauce (condiment) - ketchup
torch - flashlight
travel cot - playard
trolley (shopping) - cart
tunic - jumper
ute (utility truck) - pickup truck
zed (alphabet) - zee
4WD (4 wheel drive) - SUV