at the present time, Died in Military covers any death of in service personnel not Killed in Action.
Definition for Killed in Action is death from enemy action, either immediate or from wounds and died before reaching medical treatment at aid station, hospital, etc,
since there are so many possibilities for death, we have been thinking add a couple more to break things down a little more to group service related causes and generic health, living conditions, etc
Died of Wounds - battle related wounds being the primary cause of death within a short timeframe, days/weeks/maybe months. if someone died years later it does not fall into this category, even if the claim was death due to being gassed in the war causing other complications, infections from amputation site, etc.
Died while Prisoner - starvation, mistreatment, shot while attempting to escape, disease, etc
Died of Disease - no so prevalent today, but before medical treatments were more effective... more people died of disease in the American Civil War than were killed in action.
Died in Military Service - then becomes a catch all for both peace and wartime deaths due to vehicle accidents, heart attacks, training incidents, falling in the bathtub, bar fights, suicide, etc.
keith