The lowest rank of a commissioned officer in the United States Army, United States Air Force, or United States Marine Corps, below a first lieutenant. The rank of second lieutenant is equivalent to the naval rank of ensign
A second lieutenant is an officer in the army who ranks directly below a lieutenant
A second lieutenant is an officer in the army, air force, or marines who ranks directly below a first lieutenant. a middle rank in several of the US and British military forces, or someone who has this rank
a commissioned officer in the army or air force or marine corps holding the lowest rank