An army is a large organized group of soldiers trained to fight on land. Armies are typically part of a country's military and are responsible for defending the nation against threats, maintaining peace, and carrying out missions. They can be composed of various units, including infantry, artillery, and armored divisions, each with specific roles and equipment. Armies often participate in training exercises to prepare for combat and improve their skills. They may also engage in humanitarian efforts, such as disaster relief and peacekeeping missions. Notable examples of armies include the United States Army, the British Army, and the Indian Army.