*** Welcome to piglix ***

Lieutenant-Commander

Navies Armies Air forces
Commissioned and Non-commissioned officers
Admiral of
the fleet
Marshal or
Field marshal
Marshal of
the air force
Admiral General Air chief marshal
Vice admiral Lieutenant general Air marshal
Rear admiral Major general Air vice-marshal
Commodore Brigadier or
Brigadier general
Air commodore
Captain Colonel Group captain
Commander Lieutenant colonel Wing commander
Lieutenant
commander
Major or
Commandant
Squadron leader
Lieutenant Captain Flight lieutenant
Sub-lieutenant Lieutenant or
First lieutenant
Flying officer
Ensign Second lieutenant Pilot officer
Midshipman Officer cadet Flight cadet
Enlisted grades
Warrant officer or
Chief petty officer
Warrant officer or
Sergeant major
Warrant officer
Petty officer Sergeant Sergeant
Leading seaman Corporal Corporal
Seaman Private Aircraftman

Lieutenant commander (also hyphenated lieutenant-commander and abbreviated Lt Cdr,LtCdr. or LCDR) is a commissioned officer rank in many navies. The rank is superior to a lieutenant and subordinate to a commander. The corresponding rank in most armies (armed services) and air forces is major, and in the Royal Air Force and other Commonwealth air forces is squadron leader.

The NATO rank code is mostly OF-3.

A lieutenant commander is a senior department officer or the executive officer (second-in-command) on many warships and smaller shore installation, or the commanding officer of a smaller ship/installation. They are also senior department officers in naval aviation squadrons.

Most Commonwealth and other navies address lieutenant commanders by their full rank or the positions they occupy ("Captain" if in command of a vessel). The United States Navy, however, addresses officers by their full rank or the higher grade of the rank. For example, oral communications in formal and informal situations, a Lieutenant (junior grade) is abbreviated as "Lieutenant," and a Lieutenant Commander is abbreviated as "Commander."

Lieutenants were commonly put in command of smaller vessels not warranting a commander or captain. Such a lieutenant was called a "lieutenant commanding" or "lieutenant commandant" in the United States Navy, and a "lieutenant in command," "lieutenant and commander," or "senior lieutenant" in the Royal Navy. The USN settled on "lieutenant commander" in 1862 and made it a distinct rank. The RN followed suit in March 1914.


...
Wikipedia

...