In wartime, you'll hear the word casualty used often for someone killed or injured. But casualty can also refer to deaths or injuries suffered in an accident or some other unfortunate event.
The term "casualties of war" has been around for a while and refers to the ugly downside of military victory. Anyone who loses life or limb, either in the fighting or as a civilian, is called a casualty. If you're feeling poetic, though, you can extend the meaning to include, say, the children of a divorce: while they don't die and aren't physically injured, their emotional suffering qualifies them to be called casualties of their parents' fighting. Driving drunk, too, results in casualties.