lieutenant

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A commissioned rank in the U.S. Navy or Coast Guard that is above lieutenant junior grade and below lieutenant commander.
2. n. A first lieutenant.
3. n. A second lieutenant.
4. n. One who holds the rank of lieutenant, first lieutenant, or second lieutenant.
5. n. A commissioned officer in the British and Canadian navies ranking just below a lieutenant commander.
6. n. An officer in a police or fire department ranking below a captain.
7. n. One who acts in place of or represents a superior; an assistant or deputy: the organized crime figure and his lieutenants. See Synonyms at assistant.

Century Dictionary and Cyclopedia

1. n. In general, one who holds the place of another in the performance of any duty or function; one authorized to act in lieu of another, or employed to carry out his will or purposes; the substitute or representative of a superior.
2. n. One who holds an office, civil or military, in subordination to or as the representative of a superior; an officer authorized to perform certain functions in the absence or under the orders of another: as, the lieutenant of the Tower of London; the lord lieutenant of Ireland or of an English county (considered the direct representative of the sovereign). Particularly— In the army, a commissioned officer next in rank below a captain, and commanding the company in his absence. In the United States this officer is called first lieutenant, and has under him a subordinate officer called second lieutenant.
3. n. In archery, the winner of a lieutenancy in a shooting-match.

Wiktionary

1. n. military The lowest commissioned officer rank or ranks in many military forces.
2. n. A person who executes the plans and directives of another.
3. adj. A military grade that is junior to the grade the adjective modifies: lieutenant colonel, lieutenant general, lieutenant commander.

GNU Webster's 1913

1. n. An officer who supplies the place of a superior in his absence; a representative of, or substitute for, another in the performance of any duty.
2. n. A commissioned officer in the army, next below a captain.
3. n. A commissioned officer in the British navy, in rank next below a commander.
4. n. A commissioned officer in the United States navy, in rank next below a lieutenant commander.

WordNet 3.0

1. n. a commissioned military officer
2. n. an assistant with power to act when his superior is absent
3. n. an officer in a police force
4. n. an officer holding a commissioned rank in the United States Navy or the United States Coast Guard; below lieutenant commander and above lieutenant junior grade