a marking post or tower for guiding aviators, frequently used in races.
2.
a relatively tall structure at the side of a gate, bridge, or avenue, marking an entrance or approach.
3.
a monumental tower forming the entrance to an ancient Egyptian temple, consisting either of a pair of tall quadrilateral masonry masses with sloping sides and a doorway between them or of one such mass pierced with a doorway.
4.
a steel tower or mast carrying high-tension lines, telephone wires, or other cables and lines.
5.
Aeronautics. a finlike device used to attach engines, auxiliary fuel tanks, bombs, etc., to an aircraft wing or fuselage.
1823, "gateway to an Egyptian temple," from Gk. pylon "gateway," from pyle "gate," of unknown origin. Meaning "tower for guiding aviators" (1909) led to that of "steel tower for high-tension wires" (1923).