Military rank is a system used to classify members of the armed forces based on their level of authority, responsibility, and experience. Ranks are typically organized in a hierarchical structure, with higher ranks holding more power and command over lower ranks. Each branch of the military, such as the Army, Navy, or Air Force, has its own specific ranks and insignia. Promotion through the ranks usually requires a combination of time in service, performance evaluations, and completion of required training or education. Ranks can vary significantly between countries, but they generally serve the same purpose of establishing order and discipline within military organizations.