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.
Princeton's WordNet(0.00 / 0 votes)Rate this definition: 1  preemptive bid, pre-empt, preempt(verb) a high bid that is intended to prevent the opposing players from bidding. 2  preempt(verb) acquire for oneself before others can do so. 3  preempt, displace(verb) take the place of or have precedence over.