As in most militaries, members of the . Armed Forces hold a rank, either that of officer , warrant officer , or enlisted , to determine seniority and eligibility for promotion. Those who have served are known as veterans . Rank names may be different between services, but they are matched to each other by their corresponding paygrade .  Officers who hold the same rank or paygrade are distinguished by their date of rank to determine seniority, while officers who serve in certain positions of office of importance set by law, outrank all other officers in active duty of the same rank and paygrade, regardless of their date of rank.  Currently, only one in four persons in the United States of the proper age meet the moral, academic and physical standards for military service.