Lieutenant junior grade

Lieutenant junior grade (also called junior lieutenant, lieutenant j.g., or just j.g.) is a military rank used in Federation Starfleet from the 2280s through the 24th century, immediately superior to ensign and immediately subordinate to lieutenant. The corresponding rank in the marines is first lieutenant.

Officers with rank lieutenant j.g. are addressed as 'lieutenant'.

In the Starfleet Starfighter Corps the equivalent rank is:
 * Flying officer
 * Lieutenant jg

History
The term comes from the United States Navy of the 20th century. The USN abbreviation was LTJG.

The corresponding term in Commonwealth navies, including the Royal Navy of Britain, was sub-lieutenant. The RN has no equivalent of ensign, so sub-lieutenant was the most junior officer rank.

The Earth Starfleet of the 22nd century may not have had this rank, so that the rank immediately below lieutenant was ensign.


 * The costume department for ENT did not have an insignia for it, so it never appeared on screen.

In the 2260s a single broken sleeve stripe was used as the insignia for junior lieutenants.


 * This only appeared on screen once. Characters without sleeve stripes were variously addressed as 'crewman', 'ensign', or 'lieutenant'. Can we interpret the last as having recently been promoted to lieutenant j.g. but not got around to upgrading their uniform?

In the 2270s this was instead used to mean ensign, and there was no lieutenant j.g. rank. 

From the 2280s the lieutenant j.g. rank had a distinctive rank pin.

Insignia

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