Lieutenant (noun)

1. A rank of officer in the armed forces, typically above that of a second lieutenant and below that of a captain.
2. An officer appointed to assist a more senior officer.
3. A police officer ranking above a sergeant and below a captain.

Origin:

Middle english: from old french lieu tenant, literally "holding a place", present participle of tenir "to hold", from latin tenere.

Examples:

1. He was promoted to lieutenant.
2. She is a lieutenant in the army.
3. The lieutenant governor.
4. The lieutenant commander.
5. The lieutenant colonel.