Tractor screw

1.(Aviation) A propeller screw placed in front of the supporting planes of an airplane instead of behind them, so that it exerts a pull instead of a push. Hence, Tractor monoplane, Tractor biplane, etc. This is the most common arrangement for propellers on modern airplanes.
Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.