George: A term used to refer to the most junior officer on board the ship. Often a George Ensign is assigned the most meaningless tasks as a form of hazing. Whereas the Bull Ensign is the most senior of the ensigns.
HMS: Her Majesty's Ship.
FITREP: Fitness report is an evaluation form for officers where their performance is ranked against other officers.
LCPO: Leading Chief Petty Officer. In most cases the LCPO is the most senior enlisted in a division.
Lima charlie: "I read you lima charlie," is a saying in radio communication meaning 'loud and clear.'
NOC: Network operations center. NOCs are places where networks are monitored and managed.
SCI: Sensitive Compartmentalized Information. SCI is a caveat used with classification of information, limiting access to those with the need to know and are read into specific programs.
Rank Abbreviations:
CAPT: Captain
CDR: Commander
LCDR: Lieutenant Commander
LT: Lieutenant
LTJG: Lieutenant (sometimes just called JG)
ENS: Ensign
CPO: Chief Petty Officer