propeller

from The American Heritage® Dictionary of the English Language, 4th Edition

• n. A machine for propelling an aircraft or boat, consisting of a power-driven shaft with radiating blades that are placed so as to thrust air or water in a desired direction when spinning.

from Wiktionary, Creative Commons Attribution/Share-Alike License

• n. One who, or that which, propels.
• n. A mechanical device, with shaped blades that turn on a shaft, to push against air or water, especially one used to propel an aircraft or boat.
• n. A steamboat thus propelled; a screw steamer.

from the GNU version of the Collaborative International Dictionary of English

• n. One who, or that which, propels.
• n. A contrivance for propelling a steam vessel, usually consisting of a screw placed in the stern under water, and made to revolve by an engine; a propeller wheel.
• n. A steamboat thus propelled; a screw steamer.

from The Century Dictionary and Cyclopedia

• n. One who or that which propels; in marine engineering, broadly, any contrivance or appliance, as a sail, paddle, oar, paddle-wheel, screw, etc., used for moving vessels floating upon the surface of water, or under the surface; in a more restricted and more generally accepted sense, any instrument or appliance, and especially a screw, used for marine propulsion and actuated by machinery (usually a steam-engine called a marine engine) carried by the vessel so propelled.
• n. A boat or vessel driven by a propeller.
• n. In fishing, a kind of trolling-hook with artificial bait, fitted with wings or flanges to make it spin in the water; a spinning-bait.
• n. See the qualifying words.
• n. In electricity, in the tangential system of traction, the moving part of the system, corresponding to the rotor of an alternator, which is drawn along by the inductive action of the stator-coils between the track and thus affords motive power for the attached cars.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• n. a mechanical device that rotates to push against air or water