Real World Definition
Vice Admiral is a naval rank equivalent to Lieutenant General in seniority. A Vice Admiral is typically senior to a Rear Admiral and junior to an Admiral. In many navies, Vice Admiral is a three star rank.
History of the Insignia
The rank insignia for a Vice Admiral usually involves three stars, but this is not always the case. In the navy of Iraq, Vice Admiral insignia involves one star. In the navies of Azerbaijan, Bangladesh, China, Cuba, Iran, Mexico, North Korea, and Russia Vice Admiral insignia involves two stars, and in the navy of Turkey, Vice Admiral insignia involves four stars.
Definition in the Star Trek Universe
Vice admiral is a military rank, the equivalent of which was used by the service organizations of many civilizations. As a traditional grade, vice admiral was a flag officer falling superior to a rear admiral and below a full admiral of a naval organization. This rank was used by the Federation Starfleet (as well as its predecessor the Earth Starfleet). Vice admirals commanded entire fleets of vessels, divisions at Starfleet Headquarters, starbases, and other senior positions in the fleet. In comparison to other ranking systems, this rank was equivalent to the army lieutenant general rank or (approximately) the Cardassian Union's quasi-military rank of legate.
In the Earth organization, vice admirals (such as Maxwell Forrest) were denoted by three rank insignia enclosed in a rectangular frame, worn on both sides of a uniform jacket. These officers also had a series of rank stripes on their sleeve, a group of five stripes (four in a group, and one separate towards the cuff). (ENT: "Broken Bow")
By 2161, the sleeve stripes had changed to be more in line with the style used in the 2260s. An unnamed vice admiral (played by Manny Coto) at the signing of the Federation Charter wore a solid white/grey stripe with silver braiding (about three standard stripes wide), flanked by two single stripes of a similar material (one above and one below). (ENT: "These Are the Voyages...")
In the subsequent Federation fleets, vice admirals (like Fitzpatrick) were again denoted by sleeve stripes, this time signified by a similar insignia, one solid gold band (about three stripes wide, worn by the rank of Commodore) of braid, and two additional stripes separate, above and below. (TOS: "The Trouble with Tribbles")
By the Starfleet uniform design of the 2280s, all officers wore their insignia as a pin device attached to the shoulder on the jacket clasp. The vice admiral pin was a small round field with four gold arrowheads arranged pointing towards a gold pip in the center, and was accompanied by an embroidered sleeve stripe. (Star Trek IV: The Voyage Home)
Use of the rank in Star Trek: Second Fleet Online
The rank of Vice Admiral in Star Trek: Second Fleet Online would be used when at least one full brigade has been established (when the RPG has between 250 to 500 active members). They would oversee all of the operations in ST: SFO as well as has administrative capabilities on the ST: SFO Forums and other sites. They are responsible for appointing the promotions of the flag officers.
Currently there are no Vice Admirals in Star Trek: Second Fleet Online. This rank is offered in the Command Division only.