rudder

A vertically hinged plate of metal, fiberglass, or wood mounted at the stern of a ship or boat for directing its course.

A similar structure at the tail of an aircraft, used for effecting horizontal changes in course.

A controlling agent or influence over direction; a guide.

A riddle or sieve.

An obsolete form of rother.

That part of the helm which is abaft the stern-post, and is turned by the tiller so as to expose its side more or less to the resistance of the water and thus direct the ship’s course. It is usually hinged on the stern-post by pintles and gudgeons.

That which guides or governs the course.

. A kind of paddle to stir with.

A bird’s tail-feather; a rectrix: as, “rectrices, rudders, or true tail-feathers,”