military affairs; military matters
Refers broadly to matters concerning armed forces, defense, and warfare. Often used in compounds like 軍事力 (military power) or 軍事演習 (military exercises).
その国は軍事費を増やしている。
That country is increasing its military spending.
Knowledge about military affairs is necessary.
That country has been rapidly strengthening its military power in recent years.
The UN considered military intervention in the civil war.
The government cut military spending due to fiscal difficulties.
Military tension is rising near the border.
military science; military studies
military offense; military crime