rudder

/ˈrʌdər/

/ˈrʌdə/

Other forms: rudders

A rudder is an important part of a ship, boat, or airplane's steering system. If your rudder is out of whack, you may end up somewhere that you don't want to be!

A ship's rudder is a flat sheet attached to the stern (or back), that moves back and forth as the captain steers. It works by directing the water to move past the ship in a certain way, pushing the front of the vessel to the right or left. On an airplane, the rudder works the same way, but by directing the flow of air instead, so the plane turns to the left or right. The word rudder comes from the Old English roðor, "paddle or oar," from a Germanic root meaning "tool for steering."

Definitions of rudder

1. noun

   (nautical) steering mechanism consisting of a hinged vertical plate mounted at the stern of a vessel
   type of:

   steering mechanism, steering system

   a mechanism by which something is steered (especially a motor vehicle)
2. noun

   a hinged vertical airfoil mounted at the tail of an aircraft and used to make horizontal course changes
   type of:

   aerofoil, airfoil, control surface, surface

   a device that provides reactive force when in motion relative to the surrounding air; can lift or control a plane in flight