Толковый словарь английского языка - rudder

noun Etymology: Middle English rother, from Old English rōther paddle; akin to Old English rōwan to row Date: 14th century an underwater blade that is positioned at the stern of a boat or ship and controlled by its helm and that when turned causes the vessel's head to turn in the same direction, a movable auxiliary airfoil on an airplane usually attached at the rear end that serves to control direction of flight in the horizontal plane, a guiding force or strategy, ~less adjective