A Marine’s rank determines their status and power. Don’t confuse this with a Marine’s “grade”, which is more of a pay grade. Every branch of the military pays the same base rates for various ranks, but they do have different names for the ranks.
In the Marine Corps, the lowest enlisted rank is called “Private”. That’s the rank of all newly enlisted Marines entering boot camp. The “grade”, however, is called E1. In the army, an E1 is also called a private. In the navy, an E1 is called a seaman recruit, and so on. Some privates will move on to pay grade E2 upon graduating boot camp. The highest pay grades is E9.
There are three categories of rank. They are: enlisted personnel, Warrant Officers, and Commissioned Officers. All Commissioned Officers outrank all Warrant Officers and all Warrant Officers outrank all enlisted Marines. This means that a E9 Warrant Officer would be outranked by an E1 Commissioned Officer.
You can tell what a Marine’s rank is by the stripes and bars on their uniform. These stripes and bars are referred to as their “insignia”.