Plain English Meaning
A flat shape with four sides, where the top and bottom are parallel but one is shorter than the other. When you look at a runway during approach, it looks like this shape — wider close to you, narrower in the distance.
Full Definition
A four-sided geometric shape with one pair of parallel sides of unequal length. In the context of a stabilized approach, the runway and its surroundings appear as a trapezoid in the windshield — wider at the near end (the threshold) and narrowing toward the far end of the runway, with the runway edges forming the two non-parallel sides.
Context Anchor
Seen in stabilized approach discussions when describing what the runway should look like from the cockpit during the approach.
Derivation
From the Greek 'trapezion,' meaning 'a little table.' A small table seen from the side has a flat top and a flat bottom of different widths — the same shape a runway projects when viewed from the cockpit on final approach.
Why Pilots Care
Provides an immediate visual confirmation that the aircraft is on the correct without relying solely on instruments.