The first time I noticed this confusion was when I heard a news report of some accident or other. They report went something like:
"An accident in North England has resulted in 8 casualties. No fatalities have been reported."
I was so confused! If the first sentence was true, then how could the second also be true?!?
In America, if a news story reports a casualty, that's really bad news. It means that someone has died.
But then I remembered something. There's a show here called....
And it's not a show about death (always... obviously sometimes patients die), but rather a show about the Casualty Department at Holby City Hospital (a fictional hospital that is the subject of a different show). The Casualty Department, also known as A&E (Accident and Emergency) is the equivalent of the ER.
Here a casualty simply means an injury. Very confusing for a poor, unsuspecting American! So if you're ever injured in England and someone asks you if you need to go to Casualty, don't worry... they aren't implying that it's so bad you'll die.