ミサイル防衛[misairubouei] missile defence
共同防衛[kyoudoubouei] joint defense
攻防[koubou] offense and defense
攻防戦[koubousen] battle
国防[kokubou] national defence

国防総省[kokubousoushou] National Military Establishment
国防長官[kokubouchoukan] Secretary of Defence (Defense)
国防費[kokubouhi] defence expenditure
砂防[sabou] erosion control
酸化防止剤[sankaboushizai] antioxidant