1. (nautical) steering mechanism consisting of a hinged vertical plate mounted at the stern of a vessel
   "The captain adjusted the rudder to change the ship's course"
    
2. A hinged vertical airfoil mounted at the tail of an aircraft and used to make horizontal course changes
   "The pilot used the rudder to keep the plane steady in the crosswind"

Derived forms: rudders

Type of: aerofoil [Brit], airfoil [N. Amer], control surface, steering mechanism, steering system, surface

Part of: vertical tail, vessel, watercraft

Encyclopedia: Rudder, Michael