Definition
A pattern of white longitudinal stripes painted across the approach end of a runway to identify the beginning of the surface available for landing. On runways serving precision instrument approaches, the number of stripes encodes runway width: 4 stripes for 60 ft, 6 for 75 ft, 8 for 100 ft, 12 for 150 ft, and 16 for 200 ft. On non-precision runways, a simpler set of eight stripes (four per side) may be used regardless of width.
Plain English
The wide white stripes painted across the start of the runway. They show pilots exactly where the landing surface begins, and the number of stripes tells you how wide the runway is.
Context Anchor
Seen while approaching to land, during runway identification, and when learning airport markings.
Derivation
‘Threshold’ comes from Old English ‘þerscold’, meaning the doorway or entry point of a building. Used here in the same spirit: the threshold is the doorway onto the runway, and the markings mark that doorway.
Why Pilots Care
They establish the exact point where landing can begin, preventing short landings and ensuring proper alignment with the runway environment.
Intuition Check
Do not assume the threshold is always the very end of the pavement. Here, threshold means the marked beginning of the runway area available for landing.
Example Sentence 1
On short final, the pilot aimed just past the runway threshold markings to ensure the wheels touched down on the landing surface.
Example Sentence 2
Reviewing the airport diagram, the pilot noted the position of the runway threshold markings before the approach.