from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A vertically hinged plate of metal, fiberglass, or wood mounted at the stern of a ship or boat for directing its course.
- n. A similar structure at the tail of an aircraft, used for effecting horizontal changes in course.
- n. A controlling agent or influence over direction; a guide.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. An underwater vane used to steer a vessel. The rudder is controlled by means of a wheel, tiller or other apparatus (modern vessels can be controlled even with a joystick or an autopilot).
- n. A control surface on the vertical stabilizer of a fixed-wing aircraft or an autogyro. On some craft, the entire vertical stabilizer comprises the rudder. The rudder is controlled by foot-operated control pedals.
from the GNU version of the Collaborative International Dictionary of English
- n. A riddle or sieve.
- n. The mechanical appliance by means of which a vessel is guided or steered when in motion. It is a broad and flat blade made of wood or iron, with a long shank, and is fastened in an upright position, usually by one edge, to the sternpost of the vessel in such a way that it can be turned from side to side in the water by means of a tiller, wheel, or other attachment.
- n. Fig.: That which resembles a rudder as a guide or governor; that which guides or governs the course.
- n. In an aircraft, a surface the function of which is to exert a turning moment about an axis of the craft.
from The Century Dictionary and Cyclopedia
- n. 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.
- n. That which guides or governs the course.
- n. . A kind of paddle to stir with.
- n. A bird's tail-feather; a rectrix: as, “rectrices, rudders, or true tail-feathers,”
- n. A riddle or sieve.
- n. An obsolete form of rother.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a hinged vertical airfoil mounted at the tail of an aircraft and used to make horizontal course changes
- n. (nautical) steering mechanism consisting of a hinged vertical plate mounted at the stern of a vessel
Middle English ruder, from Old English rōther, steering oar.(American Heritage® Dictionary of the English Language, Fourth Edition)
Old English rōþor ("rudder"), from Proto-Germanic *rōþran (“rudder"; literally, "paddle, instrument for rowing”), from Proto-Germanic *rōanan "to row" from Proto-Indo-European *ere-, *rē- (“to row”) + Proto-Germanic *-þran, *-þraz, instrumental suffix. Akin to Old English rōwan ("to row"). More at rōwan, -þor. (Wiktionary)