Lieutenant colonel
From Halopedia, the Halo wiki
Template:Ratings Template:Rank Infobox Lieutenant Colonel is a field-grade commissioned officer rank of the Marine Corps; Army and Air Force, equal in rank to Commander in the UNSC Navy.
Lieutenant Colonels typically command battalions in the Army or Marines, or squadrons in the Air Force.
In informal settings, Lieutenant Colonels are referred to simply as "Colonel."