Defense Health Agency. The Defense Health Agency (DHA) is a joint, integrated Combat Support Agency that enables the U.S Army, U.S Navy, and U.S Air Force medical services to provide a medically ready force and ready medical force to Combatant Commands in both peacetime and wartime.
Definition of preemption. 1a : the right of purchasing before others; especially : one given by the government to the actual settler upon a tract of public landb : the purchase of something under this right.
Preempt (v. t. & i.) To acquire or take for oneself first (an object or right), thereby preventing others from acquiring; to appropriate; to arrogate. Preempt (v. t. & i.) To supplant or take the place of (an action), due to changes in circumstances or priorities; as, the regular meeting was preempted by an emergency conference. Preempt (v. t. & i.)