Wounded in action (WIA) describes combatants who have been wounded while fighting in a combat zone during wartime, but have not been killed. Typically it implies that they are temporarily or permanently incapable of bearing arms or continuing to fight.
For the U.S. military, becoming WIA in combat generally results in subsequent conferral of the Purple Heart, because the purpose of the medal itself (one of the highest awards, military or civilian, officially given by the American government) is to recognize those killed, incapacitated, or wounded in battle.
Wounded in action
A battle casualty other than killed in action who has incurred an injury due to an external agent or cause. The term encompasses all kinds of wounds and other injuries incurred in action, whether there is a piercing of the body, as in a penetrating or perforated wound, or none, as in the contused wound; all fractures, burns, blast concussions, all effects of biological and chemical warfare, the effects of exposure to ionizing radiation or any other destructive weapon or agent.
Died of wounds received in action
A battle casualty who dies of wounds or other injuries received in action, after having reached a medical treatment facility. In the USA the acronym used is DOW, whereas NATO uses DWRIA.