Yup Roy, and additionally, a Lieutenant of any rank is called "Lieutenant."
"Field Grade" are the mid-range officers in the Army (Junior, Field, Senior, General)
From the Wikipedia page:
Today, a field officer in the United States (here called field grade) Army, Marine Corps, and Air Force is typically a major, lieutenant colonel, or a colonel:
The [U.S.] officer corps is divided into 10 Commissioned Officer pay grades (O-1 through O-10) and 5 Warrant Officer pay grades (WO1 through CW5):
Officers in pay grades O-1 through O-3 are considered junior, or company grade, officers in the Army, Marine Corps, and Air Force. These pay grades correspond to the ranks of: second lieutenant (O-1), first lieutenant (O-2), captain (O-3) as well as Warrant Officer 1 (WO1) and Chief Warrant Officer 2 (CW2).
Commissioned Officers in the next three pay grades (O-4 through O-6) are considered field grade officers in the Army, Marine Corps, and Air Force. These pay grades correspond to the ranks of: major (O-4), lieutenant colonel (O-5), colonel (O-6). The divisions of company grade and field grade are not used by the Navy or Coast Guard. In those services the divisions are junior officers and senior officers.
In the Navy or Coast Guard, officers in pay grades O-1 through O-4 or are considered junior officers: ensign, lieutenant junior grade, lieutenant and lieutenant commander.
In the Navy or Coast Guard, officers in the following pay grades (O-5 and O-6) are considered senior officers: commander and captain.
The highest four pay grades are reserved for general officers in the Army, Marine Corps, and Air Force, and flag officers in the Navy and Coast Guard. The ranks associated with each pay grade are as follows: in the Army, Marine Corps, and Air Force, brigadier general (O-7), major general (O-8), lieutenant general (O-9), and general (O-10); in the Navy and Coast Guard, rear admiral-lower half, rear admiral-upper half, vice admiral, and admiral.