A military casualty need not be dead, or even wounded
When a report lists casualties, many people read it as a death toll. In military usage the word is far broader: a deserter, a prisoner, a soldier laid low by illness or a missing sailor all count. What matters to a commander is simply who can no longer fight.
Armies define a casualty as any service member, combatant or not, who becomes unavailable for duty. Death is one route, but so are injury, disease, psychological trauma, capture, going missing and desertion. Someone who is hurt yet can keep fighting does not count. The logic is practical: in the middle of a battle or campaign, the key question is how many members of a unit are out of action, whatever the reason. The word has carried this military sense since at least 1513.
NATO splits the category further, and military historians have widely adopted its terms. A battle casualty results directly from hostile action, whether in combat or on the way to and from a mission. A non-battle casualty is lost to disease or injury, or goes missing in circumstances that seem neither voluntary nor caused by the enemy. Other labels separate those killed in action, missing in action, wounded in action and captured. A medical casualty is anyone incapacitated by wounds or disease in a combat zone or admitted for treatment for more than a day, with a further split between cases caused by fighting and those that are not.
Missing in action is the most uncertain entry. A person reported missing might have deserted, been taken prisoner, been wounded or been killed, and the label deliberately does not choose. Civilians killed or injured by military action are counted separately, and the phrase collateral damage is sometimes used for them as a euphemism.
Outside the military, the word entered everyday use around 1844, meaning anyone killed, hurt or incapacitated by some event, usually a disaster or violent incident with many victims. The confusion with fatalities persists, even though survivors with injuries are casualties too. For scale, the World Health Organization's 2004 report estimated that intentional injuries, including war, violence and suicide, caused about 2.8 percent of deaths worldwide, while accidental injuries caused about 6.2 percent.
Source: Casualty (person)
