first lieutenant

first lieutenant (plural first lieutenants)

1. (military) The second lowest rank of a commissioned officer in the United States Army, Air Force, or Marine Corps, ranking above a second lieutenant and below a captain. The rank of first lieutenant is equivalent to the naval rank of lieutenant junior grade.
2. (military) An equivalent rank in other military forces.

When used as a title, it is always capitalized.

• Example: First Lieutenant John Smith. The rank of first lieutenant corresponds to pay grade O-2.

Abbreviations: 1st Lieutenant, 1st Lt., 1st LT, and 1LT.

• lieutenant (abbreviation of "first lieutenant")

(highest lieutenant rank):

• lieutenant senior grade