lieutenant colonel

lieutenant colonel (plural lieutenant colonels or lieutenants colonel)

1. An army officer in most countries, ranking below a colonel and above a major. Often the commander of a battalion or the executive officer of a regiment.
2. An officer in the United States Marine Corps or Royal Marines, of equivalent rank to their counterparts in the army.
3. An officer in the United States Air Force, Air Force Reserve, or Air National Guard, ranking below colonel and above major. Often the commander of a squadron or the executive officer of a wing.

When used as a title, it is always capitalized.

Example: Lieutenant Colonel John Doe.

The rank corresponds to pay grade O-5. Abbreviations: LTC.

• Officer Ranks and Insignia, US Dept. of Defense