Defense refers to the measures taken by a nation to protect itself from external threats, including military attacks and espionage. It encompasses a wide range of activities, from the development of advanced weaponry to the establishment of strategic alliances with other nations. The goal of defense is to ensure the safety and sovereignty of a country. In modern times, defense strategies have evolved to include cyber defense, intelligence gathering, and counter-terrorism efforts. Nations invest heavily in their defense systems to deter potential aggressors and maintain peace. Effective defense not only relies on military strength but also on diplomacy and international cooperation.