Vice Admiral Rank Insignia
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 could command multiple fleets of vessels or a single large fleet, divisions at Starfleet Headquarters, starbases, and other senior positions in Starfleet. In comparison to other ranking systems, this rank was equivalent to the M.A.C.O. Lieutenant General rank or (approximately) the Cardassian Union's quasi-military rank of Legate.
A famous example of a Vice Admiral was Vice Admiral William Ross, who was the Theater Commander during the Dominion War, and oversaw Starfleet operations for the duration.