Casualty ( person ) A casualty in military usage is a person in military service , not necessarily a combatant , who becomes unavailable for duty due to death , injury , illness , capture , desertion , etc . ; or a civilian casualty . In civilian usage the word " casualty " is properly used for a person who is killed , wounded or injured by some event , and is usually used to describe multiple deaths and injuries due to violent incidents or disaster s . " Casualties " is sometimes loosely used or ( mis ) understood to mean " fatalities " , but non - fatal injuries are also casualties . Military usage . In military usage , a " casualty " is a person in service killed in action , killed by disease , disabled by injuries , disabled by psychological trauma , captured , deserted , or missing , but not someone who sustains injuries which do not prevent them from fighting . Any casualty is no longer available for the immediate battle or campaign , the major consideration in combat , and the reason for lumping together all these different cases . The word has been used in a military context since at least 1513 . " Civilian casualties " are civilians killed or injured by military action , sometimes instead referred to by the euphemistic expression " collateral damage " . NATO definitions . The military organisation NATO uses the following definitions : Casualty . In relation to personnel , any person who is lost to his organization by reason of being declared dead , wounded , diseased , detained , captured or missing . Battle casualty . Any casualty incurred as the direct result of hostile action , sustained in combat or relating thereto , or sustained going to or returning from a combat mission . Non - battle casualty . A person who is not a battle casualty , but who is lost to his organization by reason of disease or injury , including persons dying from disease or injury , or by reason of being missing where the absence does not appear to be voluntary or due to enemy action or to being interned . Other definitions . These definitions are popular among military historians . Irrecoverable casualty . In relation to personnel , any person killed in action , missing in action or who died of wounds or diseases before being evacuated to a medical installation . Medical casualty . Also known as sanitary casualty . In relation to personnel , any person incapacitated by wounds sustained or diseases contracted in a combat zone , as well as any person admitted to a medical installation for treatment or recuperation for more than a day . There is a distinction between combat medical casualty and non - combat medical casualty . The former refers to a medical casualty that is a direct result of combat action ; the latter refers to a medical casualty that is not a direct result of combat action Killed in action . A casualty classification generally used to describe any person killed by means of the action of hostile forces . Missing in action . A casualty classification generally used to describe any person reported missing during combat operations . They may have deserted , or may have been killed , wounded , or become a prisoner of war . Wounded in action . A casualty classification generally used to describe any person who has incurred an injury by means of action of hostile forces . Prisoner of War . Any person who is held in custody by a hostile army during or immediately after an armed conflict . Civilian usage . While the word " casualty " has been used since 1844 in civilian life , it is a less important concept ; the number of deaths on the one hand and serious injuries on the other are separately of major importance , and immediate availability for service is not . These numbers are usually cited together with or instead of total casualties . Incidence . Military and civilian fatalities . According to WHO " World health report 2004 " , deaths from " intentional " injuries ( including war , violence , but also suicide ) were estimated to be 2 . 8 % of all deaths . In the same report , " unintentional " injury was estimated to be responsible for 6 . 2 % of all deaths .