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.

Lieutenant, company grade officer, the lowest rank of commissioned officer in most armies of the world. The lieutenant normally commands a small tactical unit such as a platoon.

LIEUTENANT definition: 1. (the title of) an officer of middle rank in the armed forces: 2. (the title of) an officer of…. Learn more.

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

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 …

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

Jan 20, 2026 · (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 …

The meaning of lieutenant differs in different militaries (see comparative military ranks), but it is often subdivided into senior (first lieutenant) and junior (second lieutenant and even third lieutenant) ranks.

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