1. (n.) A riddle or sieve.

2. (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.

3. (n.) Fig.: That which resembles a rudder as a guide or governor; that which guides or governs the course.

adjustable propeller afterburner aileron air controls air scoop aircraft airlift airplane airscrew astrodome avion balloon bay be airborne beaching gear blister body bomb bay bonnet bow brace wire bubble bubble canopy bubble hood bucket seat cabin canopy cat strip chassis chin coaxial propellers cockpit coke-bottle fuselage control surface control wires cowl crew compartment cruise deck dihedral dorsal airdome drift dual controls ejection seat ejector elevator elevon ferry fin finger patch flap flit float fly flying machine fuel injector fuselage gas-shaft hood glide gore gull wing gun mount hatch heavier-than-air craft hood hop hover hydroplane instruments jackstay jet jet pipe keel kite laminar-flow system landing gear launching gear launching tube leading edge longeron nacelle navigate nose pants parasol wing plane pod pontoon prop propeller rudder rudder bar sail sailplane seaplane ship ski landing gear slitwing soar spinner spoiler spray strip stabilizator stabilizer stay stick stick control stressed skin strut tail tail plane tail skid take the air take wing truss turret undercarriage volplane wheel parts wing wing radiator