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. You can also use this word figuratively: if a local elementary school loses funding for their art classes and after-school activities, you can say that the students are casualties of budget cuts.