The senior grade of lieutenant is known as first lieutenant in the United States, and as lieutenant in the United Kingdom and the rest of the English-speaking world.

In English, lieutenant is best known as a military title, but the word is still sometimes used in its original meaning to refer to a person who acts in lieu of someone else.

/ luˈten·ənt / Add to word list a naval officer of middle rank, above an ensign; or a military officer of the lowest rank (Definition of lieutenant from the Cambridge Academic Content Dictionary © Cambridge …

Military. first lieutenant. second lieutenant. U.S. Navy. a commissioned officer ranking between lieutenant junior grade and lieutenant commander. a person who holds an office, civil or military, in …

Definition of lieutenant noun in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

Dec 22, 2025 · (military, US) In the US Army, Air Force and Marines, holding the rank above second lieutenant and below captain. Both ranks may be referred to as " lieutenant" or as the complete forms …

If you refer to someone as a person's lieutenant, you mean they are that person's assistant, especially their main assistant, in an organization or activity. He was my right-hand man, my lieutenant on the …

LIEUTENANT meaning: 1 : an officer in the army, navy, or air force with a fairly low rank abbreviation Lt.; 2 : an officer in a fire or police department who has a rank below a captain

lieutenant noun A person who holds a position auxiliary to another and assumes some of the superior's responsibilities:

A lieutenant is a commissioned officer in the armed forces or the police who can take command if her higher-ups aren't around. Lieutenant is pronounced "loo-TEN-unt."