Lieutenant colonel

Etymology

The rank of lieutenant colonel is often shortened to simply "colonel" in conversation and in unofficial correspondence. Sometimes, the term 'half-colonel' is used in casual conversation in the British Army. Additionally, in the U.S. Army 'light colonel' has been used informally in the past. In the British military, it is customary to refer to either a lieutenant colonel or a colonel by their first names when mentioning them, e.g. "Colonel Tim will be at the parade". In the United States Air Force, the term 'light bird' or 'light bird colonel' (as opposed to a 'full bird colonel') is an acceptable casual reference to the rank but is never used directly towards the rank holder. A lieutenant colonel is typically in charge of a battalion or regiment in the army.