tractor

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A vehicle having a powerful gasoline or diesel motor and usually large, heavily treaded rear tires, used especially for pulling farm implements or machinery.
• noun A truck having a cab and no body, used for pulling large vehicles such as vans or trailers.
• noun An airplane propeller mounted in front of the supporting surfaces.
• noun An airplane having such a propeller.
• noun A toothed mechanism that automatically advances perforated continuous-form paper through a computer printer.

from The Century Dictionary.

• noun That which draws or is used for drawing; specifically, in the plural, metallic tractors. See the phrase.
• noun A traction-engine for use on streets and highways. Such tractors may be used to drag loaded vehicles, to drag plows in a gang, or to haul artillery-wagons and fieldpieces.
• noun The frame and steel rope by which a gang of plows is drawn across a field by a tractionengine.

from the GNU version of the Collaborative International Dictionary of English.

• noun That which draws, or is used for drawing.
• noun (Med.) Two small, pointed rods of metal, formerly used in the treatment called Perkinism.
• noun a motor vehicle with a powerful engine and large wheels, used to pull farm equipment such as plows, harvesting machinery, etc., over farm land. Smaller forms of farm tractor are completely open, with only a seat for the driver.
• noun a motor vehicle with a driver's cab and a powerful engine, fitted with a coupling at the rear, and designed to pull a large trailer or semi-trailer on the open highway; -- called also truck tractor. The combination of such a tractor with its trailer is called a tractor-trailer, and is a common form of truck used for commercial shipping of freight.
• noun (Aviation) A propeller screw placed in front of the supporting planes of an aëroplane instead of behind them, so that it exerts a pull instead of a push; -- called also Tractor screw and Tractor propeller.
• noun (Aviation) An airplane having one or more tractor propellers; -- called also tractor airplane.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun agriculture A vehicle used in farms e.g. for pulling farm equipment and preparing the fields.
• noun US A truck (or lorry) for pulling a semi-trailer or trailer.
• noun Any piece of machinery, any thing that pulls something.
• noun aviation (aircraft configuration) An airplane where the propeller is located in front of the fuselage
• noun archaic A metal rod used in tractoration, or Perkinism.
• adjective Having to do with tractors.

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

• noun a wheeled vehicle with large wheels; used in farming and other applications
• noun a truck that has a cab but no body; used for pulling large trailers or vans