A second lieutenant is a junior commissioned officer in the United States Army, Marine Corp and Air Force. In the Army and Marine Corp, a second lieutenant is in command of a platoon of between 16 and 44 soldiers. In the Air Force, a second lieutenant supervises flights of varying sizes as the flight commander or assistant flight commander, or he works in an administrative position.
The rank of second lieutenant is an entry-level commissioned officer rank. The insignia for a second lieutenant is a golden bar. Because of this, in the Army and Marine Corps, second lieutenants are often unofficially called "butterbars" or "nuggets."
In the Army and Marine Corps, a second lieutenant is one rank above a chief warrant officer 5 and one rank below a first lieutenant. In the Air Force, a second lieutenant is just under a first lieutenant and just above a chief master sergeant of the Air Force in rank. In the Army and Marine Corps, soldiers may enter as a second lieutenant if they have completed an ROTC program or a four-year degree and officer candidate school. During war, an exemplary enlisted soldier may receive a "battlefield commission" to second lieutenant, although this is rare.