In the U.S. Military services, rank determines who gets to tell whom what to do. The higher one's rank, the more authority, and responsibility they have.

Rank and pay grades are closely associated terms, but not quite the same. While it may take time to figure out what everything means, here are some of the terms you may want to know:

Rank: Military rank is an organizational structure that determines a service member’s responsibilities and level of leadership.

Insignia: Service members wear an assortment of emblems on their uniform to denote rank. These emblems include chevrons, bars, oak leaves or stars, and can typically be found on the shoulder or collar of the uniform.

Pay grade: There are administrative classifications designed to equalize pay across the military service branches. Each pay grade is represented by a letter and a number.

Each branch of the military has different ranks. There are four hierarchical categories:

Junior enlisted personnel: This refers to service members at the entry pay grades.

• Each service branch has a different name for their junior enlisted personnel. For example, an E-1 in the Army and Marine Corps is called a private, in the Air Force an airman basic, and in the Navy an E-1 is called a seaman recruit.
• The level at which service members are no longer considered junior enlisted personnel varies.

Non-commissioned officers:

• Enlisted service members in pay grades E-5 through E-9.
• Army, Marine Corps corporals and Navy petty officers in the pay grade of E-4.

Warrant officers:

• Service members in pay grades W-1 through W-5 of the Army and Marine Corps.
• The Coast Guard and Navy's warrant officers hold pay grades W-2 through W-4.
• The Air Force does not have Warrant Officers.

Commissioned officers:

Military commissioned officers hold the highest military ranks in the pay grades of O-1 through O-10.