An Admiral is a rank associated with the Military of a Faction, generally the leader of of a Fleet. Every government has a form of Admiral within their Rank Chart or someone who does have the same type of responsibilities.
Government Admiral Insignia
Galactic Empire's insignia for an Admiral
Anzatan Commonwhealth insignia for an Admiral
Aurodium Legion's insignia for an Admiral
Avance Coalition's insignia for an Admiral
Falleen Federation's insignia for an Admiral
The Falleen Federation have three branches where you may attain the rank of Admiral. You may attain the rank of Admiral in the Falleen Federation as a member of the Navy, State or Engineering departments.
Hapes Consortium Insignia for an Admiral
For Hapes the rank of Admiral is the final rank of the Hapan Armed Forces, after achieving the rank of Admiral you cannot progress any frther.
Mandalore Insignia for an Admiral
Whilst Mandalore have armed forces, they do not have a rank called an Admiral.
New Republic Insignia for an Admiral
Old Republic Insignia for an Admiral
Whilst the Old Republic has several ranks with the title Admiral in them, they do not have a rank devoted to the rank of Admiral.
Rogue Squadron Insignia for an Admiral
Krath Dynasty Insignia for an Admiral
The United Coalition of Rachuk Insigia for an Admiral
Tion Hegemony Insignia for an Admiral
The Tion Hegemony does not have an Admiral on it's rank chart.
Trade Federation Insignia for an Admiral
The Trade Federation does not not have an Admiral on it's rank chart.
Tresario Star Kingdom Insignia for an Admiral
Triumvirate Coalition Insignia for an Admiral
An Admiral is usually always in a psition of power in their respective factions.