fleet captain🔊noun1Government, Military, Nautical, Politics, Transport, War A captain in command of a fleet, convoy, or flotilla.2Government, Military, Nautical, Politics, Transport, War The holder of a non-flag naval rank above that of captain and below that of the admiralty ranks, having an O7 NATO rank scale equivalency.Synonymscommodore, senior captainRelated termscaptain of the fleet, commodore admiral, rear admiral lower half