A Fleet Admiral is a naval rank equivalent to Surface Marshal in seniority. A Vice Admiral is typically senior to an Admiral and junior to a Grand Admiral. The rank is often held by the most senior Admiral of an entire naval service or a senior Admiral commanding multiple fleets as opposed to just one. Fleet Admirals are addressed by rank and name; thereafter by subordinates as "Sir" or "Ma'am".It is usually abbreviated to "FAdm." or "FADM".