National defense; activities or policies related to protecting a country, including military and security measures.
国防費が増額されることになった。
It was decided that national defense spending would be increased.
災害時には国防だけでなく救援活動も重要だ。
In times of disaster, relief activities are as important as national defense.
外交と国防は密接に関連している。
Diplomacy and national defense are closely related.