Lieutenant Commander is a rank.
A traditional naval rank, Lieutenant Commander was once used in the old navies of Earth, among them the United States Navy and the Royal Navy. In these organizations, a Lieutenant Commander was a grade between the ranks of Lieutenant and Commander grades.
By the 22nd century, Lieutenant Commander had apparently become defunct and was not used in the Earth Starfleet. A century later, in the early 2260s, Lieutenant Commander was being used by Starfleet of the United Federation of Planets.
A Lieutenant Commander can serve as either the commanding officer or executive officer onboard small to medium-sized vessels or serve as the department head (in addition to being the second officer or third officer) onboard a larger vessel.
Lieutenant Commanders RanksEdit