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.
Wiktionary(0.00 / 0 votes)Rate this definition: 1  preempt(Verb) to appropriate something (before someone else does) 2  preempt(Verb) to displace something, or take precedence over something. 3  preempt(Verb) to make a preemptive bid at bridge.