The army is an armed organization serving political purposes, the protagonist of military war and the pillar of every country's security and stability. Most of the world's armed forces are divided into three services: the army, the Navy and the air force. Some countries have a more detailed division, such as the air defense force, the strategic rocket force and the Artillery Force.

Each service generally includes a number of arms, in which there are military command organs, combat and combat support forces, logistics support systems, colleges and universities, and scientific research institutions. They are equipped with special weapons and equipment, and carry out strategies and tactics, system establishment and training, management, supply, supplement and duty system reflecting their own characteristics, and have specific clothing and marks.

In short, the army is a specialized armed group set up by some political groups to safeguard their territorial integrity, people's security and social peace.

Source: @stefanrusu.c